- Average Rate of Change/Slope Formula: [tex]\frac{y_2-y_1}{x_2-x_1}[/tex]
So using points (6,71) and (2,y), and the slope of 15, plug them into the slope formula as such:
[tex]\frac{71-y}{6-2}=15[/tex]
From here we can solve for y. Firstly, solve the subtraction:
[tex]\frac{71-y}{4}=15[/tex]
Next, multiply both sides by 4:
[tex]71-y=60[/tex]
Next, subtact both sides by 71:
[tex]-y=-11[/tex]
Lastly, multiply both sides by -1, and your final answer will be [tex]y=11[/tex] , or A.
