Question

Graph the following lines and write the equation in slope-intercept form. e Through the point (2,7.5) with an x intercept of −1.

Answer 1

Given

• a line through (2, 7.5) and (-1, 0)

Find

• the line's equation in slope-intercept form

Solution

You can start with the 2-point form of the equation for a line:

... y = (y₂ -y₁)/(x₂ -x₁)·(x -x₁) +y₁

Filling in the given values, you get

... y = (0 -7.5)/(-1 -2)·(x -(-1)) +0

... y = 2.5(x +1) . . . . . simplify a bit

... y = 2.5x +2.5 . . . . slope-intercept form

Answer 2

First you find the slope with the 2 points: (2, 7.5) and (-1, 0)

y1-y2/x1-x2 so  7.5-0/2-(-1) which equals 2.5

Next you solve the slope intercept form equation to get b

y=m*x+b (m is the slope and b is the intercept)

7.5=2.5*2+b

b=2.5

So the equation is y=2.5x+2.5