How do you write an equation in slope-intercept form of the line through point P(-10,1) with slope -5?

2 Answers
May 25, 2015

Since we're given the slope and a point, let's start with point slope form.

The point slope form is:

y - y_0 = m(x - x_0)yy0=m(xx0) where mm is the slope and (x_0, y_0)(x0,y0) is a point through which the line passes.

In our case m=-5m=5 and (x_0, y_0) = (-10, 1)(x0,y0)=(10,1), so we can write:

y - 1 = -5(x - (-10)) = -5(x + 10)y1=5(x(10))=5(x+10)

Slope intercept form is:

y = mx+cy=mx+c where mm is the slope and cc the intercept.

To rearrange in slope intercept form, add 11 to both sides to get:

y = -5(x+10)+1y=5(x+10)+1

= -5x-50+1=5x50+1

= -5x - 49=5x49

This is pretty much slope intercept form with slope m=-5m=5 and intercept c = -49c=49.

If we are really picky, we might write:

y = -5x + -49y=5x+49

May 25, 2015

The equation in slope-intercept form is y=-5x-49y=5x49.

Slope-intercept form: y=mx+by=mx+b, where mm is the slope and bb is the y-intercept.

Substitute the known values into the equation, then solve for bb.

y=1 y=1m=-5=5
x=-10x=10

y=mx+by=mx+b =

1=-5(-10)+b1=5(10)+b =

1=50+b1=50+b

-49=b49=b

y=-5x-49y=5x49