Question

resolvam pfv (8a-5)²

Answer 1

(8a -5) . (8a -5)

64a² -40a -40a +25 
64a² -80a +25 = 0

Δ = 6400 -4 . 64 . 25
Δ = 0

a = 80/2 . 64
a = 80/128  ⇒ 10/16 ⇒ 5/8

S = {5/8}