Answer:
see explanation
Step-by-step explanation:
The diagonals of a parallelogram bisect each other, hence
AE = EC, that is
x² - 6 = 5x ( subtract 5x from both sides )
x² - 5x - 6 = 0 ← in standard form
(x - 6)(x + 1) = 0 ← in factored form
Equate each factor to zero and solve for x
x - 6 = 0 ⇒ x = 6
x + 1 = 0 ⇒ x = - 5
However x > 0 ⇒ x = 6
AC = x² - 6 + 5x = 6² - 6 + 5(6) = 36 - 6 + 30 = 60
