We are tasked to solve for the values of z using and applying the zero product property which means that we need to get the factors and equate it to be equal to zero. Such that the given expression z² - 15z + 56 = 0 will have a solution shown below:
z² - 15z + 56 = 0
The expression will have a and b values such as a = - 7 and b = -8.
z² - 15z + 56 = 0
(z -7) (z-8) = 0
solving for the first value of z, we have it:
z - 7 = 0
z = 7
Solving for the second value of z, we have it:
z - 8 = 0
z = 8
Therefore, the answer to this problem is the letter "A" which is 7 and 8.