How do you write an equation in slope-intercept form for a line containing (9,−3) and (5,5)?

2 Answers
Isini M.
Jun 7, 2017

y=−2x+15

Explanation:

The general form of a linear equation is y=mx+c where m is the gradient (slope) and (0,c) is the y-intercept.

m=y2−y1x2−x1 for a line containing (x1,y1) and (x2,y2).

For (9,−3) and (5,5),
m=5−(−3)5−9
m=−2

Therefore, y=−2x+c. To find c, substitute (5,5) into this equation.
5=−2(5)+c
c=5+10
c=15

Substitute c value back into equation,
y=−2x+15

Marvin V.
Jun 7, 2017

y=−2x+15

Explanation:

We first begin with finding out the slope using the slope formula, which

is y2−y1x2−x1. Plug in our points 5−(−3)5−9=−82=−2. This is our slope now we use the point slope formula y−y1=m(x−x1).

You can pick any of the two points, m is our slope which is −2.

y−5=−2(x−5) go ahead and solve.

You should arrive to the answer of y=−2x+15.

When you do y2−y1x2−x1 it doesn't matter which point is your (y2,x2) or (y1,x1).

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