Answer
a) y=2$x$+11
b)-$\frac{11}{2}$
Work Step by Step
a) Using $\frac{y_{2}-y_{1}}{x_{2}-x_{1}}$ to find the slope, $\frac{(9)-(5)}{(-1)-(-3)}$=$\frac{4}{2}$=2. Then, to find the y-intercept, set the equation y=mx+b using one of the coordinates given. Using either sets will produce the same answer, so in this case, we will use (-1,9). Then find $b$.
$x$=-1
y=9
m=2 (the slope found)
y=m$x$+$b$
9=2(-1)+$b$
9=-2+$b$
$b$=11
So the slope-intercept form of its equation is y=2$x$+11.
b) At the x-intercept, y=0 so set the equation to find $x$.
y=2$x$+11
0=2$x$+11
-11=2$x$
$x$=-$\frac{11}{2}$
