Asap! 20 points! i have to pass math! from the equation, what is the value of the radius, r? x^2 + y^2 = 144 asap

Explain how you can use the associative property to evaluate (7x50)x4.

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

Tom can paint the fence in 12 hours, but if he works together with a friend they can finish the job in 8 hours. how long would it take for his friend to paint this fence alone?