Answer: [tex]r = -17[/tex]
Step-by-step explanation:
The formula for calculating slope is given as:
[tex]m = \frac{y_{2}-y_{1}}{x_{2}-x_{1}}[/tex]
From the question
[tex]m = -5[/tex]
[tex]x_{1} = -4[/tex]
[tex]x_{2} = -8[/tex]
[tex]y_{1} = r[/tex]
[tex]y_{2} = 3[/tex]
substituting into the formula , we have :
[tex]-5 = \frac{3-r}{-8-(-4)}[/tex]
[tex]-5 = \frac{3-r}{-8+4}[/tex]
[tex]-5 = \frac{3-r}{-4}[/tex]
multiplying through by -4 , we have:
[tex]20 = 3-r[/tex]
add r to both sides
[tex]20+r= 3[/tex]
subtract 20 from both sides
[tex]r = -17[/tex]
