Question

Como se resolve ??
 
(x^2+2x).(x^2-2x) = 45

^ - Elevado a 2

Answer 1

$( x^{2} +2x) *( x^{2} -2x) = 45 => x^{4} - 2 x^{3} + 2x^{3} - 4 x^{2} - 45 = 0 \\ \\ x^{4} -4 x^{2} -45 =0$

(x + 3 ) * (x - 3) * (x² + 5)

x + 3 = 0 =>  x = - 3

x - 3 = 0  => x =   3

x² + 5 = 0    $x = \sqrt{-20}$