Question

x elevado a 2 -8x+12=0

Answer 1

8²-4.1.12 = 64-48=16

Answer 2

x² - 8x + 12 = 0

a = 1; b = -8; c = 12

x = [- b ± √(b² - 4ac)] / 2a
x = [- (-8) ± √([-8]² - 4 · 1 · 12)] / 2 · 1
x = [8 ± √(64 - 48)] / 2
x = [8 ± √16] / 2
x = [8 ± 4] / 2
x' = [8 + 4] / 2 = 12 / 2 = 6
x'' = [8 - 4] / 2 = 4 / 2 = 2

Espero ter ajudado. Valeu!