The sum of two numbers is 20 and their difference is 4​

The graph of the quadratic function shown on the left is y = –0.7(x + 3)(x – 4). the roots, or zeros, of the function are . determine the solutions to the related equation 0 = –0.7(x + 3)(x – 4). the solutions to the equation are x =

If x = -2, then x 2-7x+10 equals a. 0 b.20 c.28

Can someone explain to me how to do