Answer:
The value of r is 5
Step-by-step explanation:
The question is
Find out the value of r
we know that
The formula to calculate the slope between two points is equal to
[tex]m=\frac{y2-y1}{x2-x1}[/tex]
we have the points
(-3,9) and (-1,r)
substitute
[tex]m=\frac{r-9}{-1+3}[/tex]
[tex]m=\frac{r-9}{2}[/tex]
Remember that
[tex]m=-2[/tex]
substitute the value of m
[tex]-2=\frac{r-9}{2}[/tex]
Solve for r
Multiply by 2 both sides
[tex]-4=r-9[/tex]
Adds 9 both sides
[tex]-4+9=r-9+9[/tex]
[tex]5=r[/tex]
Rewrite
[tex]r=5[/tex]
