Plz in need help

Answer this question! 30 points and brainliest!

25 ! the line of best fit is h = 5a + 86. predict the height at age 16.

To solve the system of equations below, pedro isolated the variable y in the first equation and then substituted it into the second equation. what was the resulting equation? { 5y=10x {x^2+y^2=36