Question

Qual a resposta :
Função f(x) = x² -8x +7 ,determine

Answer 1

∆=b²-4.a.c

∆=(-8)²-4.1.7
∆=64-28
∆=36 √36=6

x=-b±√∆/2.a

x1=8+6/2.1
14/2
x1=7

x2=8-6/2.1
2/2
x2=1

S={7, 1}

Answer 2

f (x) = x² - 8x + 7

a = 1; b = -8; c = 7

x = [- b ± √(b² - 4ac)] / 2a
x = [- (-8) ± √([-8]² - 4 · 1 · 7)] / 2 · 1
x = [8 ± √(64 - 28)] / 2
x = [8 ± √36] / 2
x = [8 ± 6] / 2
x' = [8 + 6] / 2 = 14 / 2 = 7
x'' = [8 - 6] / 2 = 2 / 2 = 1

S = {1, 7}

Espero ter ajudado. Valeu!