Question

Resolva:
a) x⁴-16x²=0

Answer 1

Divida tudo por x² e resolva...

(x^4-16x^2)/x^2=0 
x^2-16=0
x^2=16
x=+-√16
x=+-4

Answer 2

$x^{4} - 16 x^{2} = 0 x^{2} ( x^{2} - 16)=0 x^{2} = 0 x =0 x^{2} - 16 = 0 x^{2} = 16 x = \sqrt{16} x=4 S= {0;4}$