Question

Resolva a Equação Irracional: $\sqrt[3]{ x^{2} - 7x } = 2$

Answer 1

$\sqrt[3]{ x^{2} -7x} = 2  x^{2} -7x = 2^{3}  2 x^{2} -7x =8 2 x^{2} -7x-8=0$

fórmula de Bháskara
Δ= $b^{2} -4.a.c x^{2}$
Δ= $(-7)^{2} -4.2.(-8)$
Δ= $49 +32$
Δ= $81$

x= -b ±√Δ /2.a
x= -(-7) ±√81 /2.1
x= 7 ±9 /2

x'=7+9 /2
x'=16/2
x'=8

x''= 7-9 /2
x''= -2/2
x''=-1            (não nos serve)

logo x=8