Answer:
y = -4x + 15
Step-by-step explanation:
Slope-intercept form is y = mx + b
m = slope ([tex]\frac{y_{2} - y_{1}}{x_{2} - x_{1}}[/tex])
b = y-intercept (where the line crosses the y-axis)
It doesn't matter which coordinate pair you use for (x₁,y₁).
(x₁,y₁) = (2,7)
(x₂,y₂) = (4,-1)
[tex]\frac{-1 - 7}{4 - 2}[/tex] Simplify
[tex]\frac{-8}{2}[/tex] Simplify
-4 = your slope (m)
To get this information into slope-intercept form, you have to plug it into point-slope form, y - y₁ = m(x - x₁). It doesn't matter which coordinate pair you use for (x₁,y₁).
y - y₁ = m(x - x₁) Let's use (2,7) since it doesn't have negatives.
y - 7 = -4 (x - 2) Distribute
y - 7 = -4x + 8 Add 7 to both sides
y = -4x + 15
Check your answer by plugging both coordinate pairs in.
y = -4x + 15
7 = -4(2) + 15
7 = -8 + 15
7 = 7
and
-1 = -4(4) + 15
-1 = -16 + 15
-1 = -1
