Let’s solve each problem step by step. We’ll find the equation of the line that passes through two given points. The general form we want is:
y = mx + b
Where:
-
m is the slope (how steep the line is)
-
b is the y-intercept (where the line crosses the y-axis)
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Problem 1: Points A(-6, -6) and B(6, -4)
Step 1: Find the slope (m)
Slope formula:
> m = (y₂ - y₁) / (x₂ - x₁)
Let’s use:
- Point A: x₁ = -6, y₁ = -6
- Point B: x₂ = 6, y₂ = -4
So:
m = (-4 - (-6)) / (6 - (-6))
= (-4 + 6) / (6 + 6)
= 2 / 12
=
1/6
Step 2: Use point-slope to find b
We can plug into y = mx + b using one point — let’s use point B(6, -4):
-4 = (1/6)(6) + b
-4 = 1 + b
b = -5
✔ So the equation is:
y = (1/6)x - 5
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Problem 2: Points A(-3, -1) and B(-1, 3)
Step 1: Find the slope
x₁ = -3, y₁ = -1
x₂ = -1, y₂ = 3
m = (3 - (-1)) / (-1 - (-3))
= (3 + 1) / (-1 + 3)
= 4 / 2
=
2
Step 2: Find b
Use point B(-1, 3):
3 = 2*(-1) + b
3 = -2 + b
b = 5
✔ Equation:
y = 2x + 5
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Problem 3: Points A(4, 8) and B(-4, 4)
Step 1: Slope
x₁ = 4, y₁ = 8
x₂ = -4, y₂ = 4
m = (4 - 8) / (-4 - 4)
= (-4) / (-8)
=
1/2
Step 2: Find b
Use point A(4, 8):
8 = (1/2)(4) + b
8 = 2 + b
b = 6
✔ Equation:
y = (1/2)x + 6
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Problem 4: Points A(-8, 6) and B(2, -9)
Step 1: Slope
x₁ = -8, y₁ = 6
x₂ = 2, y₂ = -9
m = (-9 - 6) / (2 - (-8))
= (-15) / (10)
=
-3/2
Step 2: Find b
Use point B(2, -9):
-9 = (-3/2)(2) + b
-9 = -3 + b
b = -6
✔ Equation:
y = (-3/2)x - 6
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Final Answer:
1. y = (1/6)x - 5
2. y = 2x + 5
3. y = (1/2)x + 6
4. y = (-3/2)x - 6
Parent Tip: Review the logic above to help your child master the concept of find the equation of a line given two points worksheet.