# How do you write the equation in slope intercept form given (1,-3) with x-intercept = -1?

Aug 9, 2016

$y = m x + b$ where $y = - \frac{3}{2} x - 1 \frac{1}{2}$

#### Explanation:

Explanation

Explanation:

In $y = m x + b$ The slope intercept form
m = the slope think m = mountain slope
b = the y-intercept think b = beginning starting point.
m ; the slope = the change in y divided by the change in x

$\frac{{y}_{2} - {y}_{1}}{{x}_{2} - {x}_{1}}$ = m

Substitute -3 for ${y}_{2}$ and 0 for ${y}_{1}$ ( y is zero at the x intercept)
Substitute 1 for ${x}_{2}$ and -1 for ${x}_{1}$ ( -1 is the x intercept)

 ( -3 - 0) / { 1 - ( -1 )  = m

m = $- \frac{3}{+ 2}$

Now, to find the y-intercept remember $x = 0$ at the y-intercept.
So one point is ( 0, b) and a second point is ( 1,-3)

$\frac{b - \left(- 3\right)}{0 - 1} = - \frac{3}{2}$

$\frac{b + 3}{- 1} = \frac{- 3}{2}$

multiplying both sides by -1 gives

$b + 3 = \frac{3}{2}$
subtracting -3 from both sides gives

$b = \frac{3}{2} - 3$

$b = - \frac{3}{2}$