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10 votes
10 votes
A line passes through the points A(–1, 7) and B(1, 3). b Write an equation

User Jason Grant Taylor
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2.5k points

1 Answer

14 votes
14 votes

Answer:

y=-2x+5

Explanation:

First, find the slope:

m=(y2-y1)/(x2-x1) ==> slope formula where m is the slope

(–1, 7), (1, 3) ==> (x1=-1, y1=7), (x2=1, y2=3)

m=(3 - 7)/(1 - (-1)) ==> plugin y2=3, y1=7, x2=1, and x1=-1 into the slope formula

m=(-4)/(1 + 1) ==> simplify

m=(-4)/2

m=-2 ==> the slope is -2

y=mx+b ==> slope-intercept equation

3=(-2)(1)+b ==> plugin the slope(m=-2) and point B(1, 3) ==> (x=1, y=3)

3=-2+b ==> solve for b

3+2=-2+2+b ==> add 2 on both sides to isolate b

b=5 ==> simplify

y=-2x+5 ==> plugin the slope and b=5 into the equation

User Guy Nachshon
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3.1k points