2
The intersection point of the lines 2x + 3y = 11 and x - 2y + 12 = 0 is P(x1, y1). The line x - 2y + 12 = 0 intersects the x-axis at Q(x2, y2). Calculate the value of (x1 - x2 + y1 + y2).
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Solution: Step 1: Find the intersection point P(x1, y1) by solving the system of equations:
(1) 2x + 3y = 11
(2) x - 2y = -12
Step 2: Multiply equation (2) by 2:
(3) 2x - 4y = -24
Step 3: Subtract equation (3) from equation (1):
(2x + 3y) - (2x - 4y) = 11 - (-24)
7y = 35
y = 5
Step 4: Substitute y = 5 into equation (1) to find x:
2x + 3*(5) = 11
2x + 15 = 11
2x = -4
x = -2
So, P(x1, y1) = (-2, 5).
Step 5: Find the point Q(x2, y2) where the line x - 2y + 12 = 0 intersects the x-axis. On the x-axis, y = 0.
x - 2*(0) + 12 = 0
x + 12 = 0
x = -12
So, Q(x2, y2) = (-12, 0).
Step 6: Calculate the value of (x1 - x2 + y1 + y2).
(-2) - (-12) + 5 + 0
= -2 + 12 + 5 + 0
= 10 + 5
= 15.
3
A line originates from the origin and intersects the line 3x - 2y = 6 perpendicularly at point M. Determine the coordinates of point M.
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Solution: Step 1: Find the slope of the given line 3x - 2y = 6.
Rearrange to slope-intercept form (y = mx + c): -2y = -3x + 6 => y = (3/2)x - 3.
So, the slope of the given line (m1) = 3/2.
Step 2: Find the slope of the line perpendicular to it.
For perpendicular lines, m1 * m2 = -1.
(3/2) * m2 = -1 => m2 = -2/3.
Step 3: Write the equation of the line passing through the origin (0, 0) with slope m2 = -2/3.
Using y - y1 = m(x - x1): y - 0 = (-2/3)(x - 0) => y = (-2/3)x => 3y = -2x => 2x + 3y = 0.
Step 4: Find the intersection point M by solving the system of equations:
1) 3x - 2y = 6
2) 2x + 3y = 0
Step 5: From equation (2), x = -3y/2.
Step 6: Substitute this x into equation (1):
3(-3y/2) - 2y = 6
-9y/2 - 2y = 6
Multiply by 2: -9y - 4y = 12
-13y = 12
y = -12/13
Step 7: Substitute y back into x = -3y/2:
x = -3/2 * (-12/13)
x = (3 * 6) / 13 = 18/13
Step 8: The coordinates of point M are (18/13, -12/13).
4
Determine the area (in square units) of the region bounded by the lines defined by the equations 2x - 3y + 6 = 0, 4x + y = 16, and y = 0.
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Solution: Step 1: Find the intersection points of the given lines to determine the vertices of the enclosed region.
Step 2: Intersection of 2x - 3y + 6 = 0 and y = 0: Substitute y=0 into 2x - 3y + 6 = 0 => 2x + 6 = 0 => 2x = -6 => x = -3. Vertex 1: (-3, 0).
Step 3: Intersection of 4x + y = 16 and y = 0: Substitute y=0 into 4x + y = 16 => 4x = 16 => x = 4. Vertex 2: (4, 0).
Step 4: Intersection of 2x - 3y + 6 = 0 and 4x + y = 16:
From 4x + y = 16, y = 16 - 4x.
Substitute into 2x - 3y + 6 = 0: 2x - 3(16 - 4x) + 6 = 0 => 2x - 48 + 12x + 6 = 0 => 14x - 42 = 0 => 14x = 42 => x = 3.
Substitute x=3 back into y = 16 - 4x: y = 16 - 4(3) = 16 - 12 = 4. Vertex 3: (3, 4).
Step 5: The vertices of the triangle are A(-3, 0), B(4, 0), and C(3, 4).
Step 6: The base of the triangle lies on the x-axis (y=0) from x=-3 to x=4. Length of base = 4 - (-3) = 7 units.
Step 7: The height of the triangle is the perpendicular distance from vertex C to the x-axis, which is the y-coordinate of C, i.e., 4 units.
Step 8: Calculate the area of the triangle: Area = (1/2) * base * height = (1/2) * 7 * 4 = 14 square units.
5
Given parallelogram ABCD with coordinates A(5, 0), B(-2, 3), and C(-1, 4), find the equation of line AD.
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Solution: Step 1: In a parallelogram, opposite sides are parallel. Therefore, line AD is parallel to line BC.
Step 2: Calculate the slope (m_BC) of line BC using points B(-2, 3) and C(-1, 4).
m_BC = (y2 - y1) / (x2 - x1) = (4 - 3) / (-1 - (-2)) = 1 / (-1 + 2) = 1 / 1 = 1.
Step 3: Since AD is parallel to BC, the slope of line AD (m_AD) is equal to m_BC.
m_AD = 1.
Step 4: Use the point-slope form of a linear equation (y - y1 = m(x - x1)) with point A(5, 0) and slope m_AD = 1.
y - 0 = 1*(x - 5).
y = x - 5.
8
A point Q(a, b) is reflected across the y-axis to obtain Q1. Then, Q1 is reflected across the x-axis, resulting in the point (-5, 3). Determine the coordinates of point Q.
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Solution: Step 1: Let the final reflected point be Q2(-5, 3). This point Q2 is the reflection of Q1 across the x-axis.
Step 2: If a point (x, y) is reflected across the x-axis, its new coordinates are (x, -y). Working backward, if Q2(-5, 3) is the reflection of Q1 across the x-axis, then Q1 must be (-5, -3).
Step 3: Now, Q1(-5, -3) is the reflection of the original point Q(a, b) across the y-axis.
Step 4: If a point (x, y) is reflected across the y-axis, its new coordinates are (-x, y). Working backward, if Q1(-5, -3) is the reflection of Q across the y-axis, then Q must be (5, -3).
Step 5: Therefore, the coordinates of point Q are (5, -3).
9
Find the ratio in which the point T(x, 0) divides the line segment connecting points S(-4, -1) and U(1, 4).
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Solution: Step 1: Let the point T(x, 0) divide the segment joining S(-4, -1) and U(1, 4) in the ratio k : 1.
Step 2: Use the section formula for the y-coordinate:
y = (k * y2 + 1 * y1) / (k + 1)
Step 3: Substitute the coordinates of S(x1, y1) = (-4, -1), U(x2, y2) = (1, 4), and T(x, y) = (x, 0).
0 = (k * 4 + 1 * (-1)) / (k + 1)
Step 4: Simplify the equation:
0 = (4k - 1) / (k + 1)
Step 5: Multiply both sides by (k + 1):
0 * (k + 1) = 4k - 1
0 = 4k - 1
Step 6: Solve for k:
4k = 1
k = 1/4.
Step 7: The ratio k : 1 is 1/4 : 1, which simplifies to 1 : 4.
Step 8: (Optional) We can also find x using the x-coordinate section formula: x = (k * x2 + 1 * x1) / (k + 1) = ((1/4)*1 + 1*(-4)) / (1/4+1) = (1/4 - 4) / (5/4) = (-15/4) / (5/4) = -15/5 = -3. So the point is T(-3, 0).
10
The line 3x + 4y = 24 intersects the x-axis at point A and the y-axis at point B. P(2, 0) and Q(0, 3/2) are points on segments OA and OB, respectively, where O is the origin. If AB = 10 cm, what is the length of PQ?
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Solution: Step 1: Find the x-intercept (point A) by setting y = 0 in the equation 3x + 4y = 24.
3x + 4(0) = 24 => 3x = 24 => x = 8. So, A = (8, 0).
Step 2: Find the y-intercept (point B) by setting x = 0 in the equation 3x + 4y = 24.
3(0) + 4y = 24 => 4y = 24 => y = 6. So, B = (0, 6).
Step 3: Identify the given points P(2, 0) and Q(0, 3/2). (Note: The information AB = 10 cm is consistent but not strictly needed to find PQ. Distance AB = sqrt((8-0)^2 + (0-6)^2) = sqrt(64+36) = sqrt(100) = 10.)
Step 4: Use the distance formula to find the length of PQ, where P=(x1, y1)=(2, 0) and Q=(x2, y2)=(0, 3/2).
Distance PQ = sqrt((x2 - x1)^2 + (y2 - y1)^2)
Step 5: Substitute the coordinates:
PQ = sqrt((0 - 2)^2 + (3/2 - 0)^2)
PQ = sqrt((-2)^2 + (3/2)^2)
PQ = sqrt(4 + 9/4)
PQ = sqrt(16/4 + 9/4)
PQ = sqrt(25/4)
PQ = 5/2
Step 6: Convert to decimal: PQ = 2.5 cm.
11
Calculate the area of the quadrilateral defined by connecting the points (4, 2), (8, 2), (8, 14), and (4, 10).
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Solution: Step 1: Label the given points as A(4, 2), B(8, 2), C(8, 14), and D(4, 10).
Step 2: Divide the quadrilateral ABCD into two triangles, for example, triangle ABC and triangle ACD.
Step 3: Calculate the area of triangle ABC using the determinant formula: Area = 1/2 |x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)|.
Step 4: For triangle ABC (A(4,2), B(8,2), C(8,14)): Area(ABC) = 1/2 |4(2 - 14) + 8(14 - 2) + 8(2 - 2)| = 1/2 |-48 + 96 + 0| = 1/2 |48| = 24 square units.
Step 5: Calculate the area of triangle ACD using the same formula.
Step 6: For triangle ACD (A(4,2), C(8,14), D(4,10)): Area(ACD) = 1/2 |4(14 - 10) + 8(10 - 2) + 4(2 - 14)| = 1/2 |16 + 64 - 48| = 1/2 |32| = 16 square units.
Step 7: The total area of the quadrilateral ABCD is the sum of the areas of triangle ABC and triangle ACD.
Step 8: Area(ABCD) = Area(ABC) + Area(ACD) = 24 + 16 = 40 square units.
12
A line passing through points (-2, 5) and (6, b) is perpendicular to the line 20x + 5y = 3. Determine the value of b.
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Solution: Step 1: Find the slope of the given line (L1): 20x + 5y = 3.
- Rearrange to slope-intercept form (y = m1x + c1): 5y = -20x + 3 => y = -4x + 3/5.
- So, the slope of L1 (m1) = -4.
Step 2: Since the line passing through (-2, 5) and (6, b) (L2) is perpendicular to L1, the product of their slopes must be -1. m1 * m2 = -1 => -4 * m2 = -1 => m2 = 1/4.
Step 3: Use the two given points for L2, (-2, 5) and (6, b), to calculate its slope (m2) using the slope formula: m = (y2 - y1) / (x2 - x1).
- m2 = (b - 5) / (6 - (-2)) = (b - 5) / 8.
Step 4: Equate the two expressions for m2 and solve for b:
- (b - 5) / 8 = 1/4
- Multiply both sides by 8: b - 5 = 8 * (1/4) => b - 5 = 2.
- Solve for b: b = 2 + 5 => b = 7.
Step 5: The value of b is 7.
14
Given that points A(3, -2), B(1, 4), and C(-2, x) are collinear, determine the value of x.
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Solution: Step 1: For three points to be collinear, the slope between any two pairs of points must be equal.
Let's calculate the slope of segment AB (m_AB) using points A(3, -2) and B(1, 4).
m_AB = (4 - (-2)) / (1 - 3) = (4 + 2) / (-2) = 6 / -2 = -3.
Step 2: Calculate the slope of segment BC (m_BC) using points B(1, 4) and C(-2, x).
m_BC = (x - 4) / (-2 - 1) = (x - 4) / -3.
Step 3: Set m_AB = m_BC since the points are collinear.
-3 = (x - 4) / -3.
Step 4: Solve for x.
(-3) * (-3) = x - 4.
9 = x - 4.
x = 9 + 4.
x = 13.
Alternate Method (using area of triangle = 0):
Step 1: For three points (x1, y1), (x2, y2), (x3, y3) to be collinear, the area of the triangle formed by them must be zero.
Area = 0.5 * |x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)| = 0.
Step 2: Substitute the coordinates A(3, -2), B(1, 4), C(-2, x).
0 = 3*(4 - x) + 1*(x - (-2)) + (-2)*(-2 - 4).
0 = 3*(4 - x) + 1*(x + 2) + (-2)*(-6).
0 = 12 - 3x + x + 2 + 12.
0 = 26 - 2x.
2x = 26.
x = 13.
17
Determine the value of x, given that the line connecting points (-3, 4) and (0, 3) is perpendicular to the line connecting points (5, 7) and (4, x).
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Solution: Step 1: Calculate the slope (m1) of the first line passing through (-3, 4) and (0, 3).
m1 = (3 - 4) / (0 - (-3)) = -1 / 3.
Step 2: Calculate the slope (m2) of the second line passing through (5, 7) and (4, x).
m2 = (x - 7) / (4 - 5) = (x - 7) / -1 = -(x - 7).
Step 3: Since the lines are perpendicular, the product of their slopes is -1 (m1 * m2 = -1).
(-1/3) * (-(x - 7)) = -1.
Step 4: Simplify the equation.
(x - 7) / 3 = -1.
Step 5: Solve for x.
x - 7 = -3.
x = -3 + 7.
x = 4.
19
Determine the coordinates of the points where the graph of the equation 57x - 19y = 399 intersects the x and y coordinate axes.
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Solution: Step 1: To find the x-intercept, set y = 0 in the equation 57x - 19y = 399.
57x - 19*(0) = 399.
57x = 399.
x = 399 / 57.
x = 7.
The x-intercept is at the point (7, 0).
Step 2: To find the y-intercept, set x = 0 in the equation 57x - 19y = 399.
57*(0) - 19y = 399.
-19y = 399.
y = 399 / -19.
y = -21.
The y-intercept is at the point (0, -21).