Respostas

2014-08-17T17:30:13-03:00
Olá, Lol99!

2x² = 15 - x²
2x² + x² = 15
3x² = 15
x² = 15 / 3
x² = 5
x = +-√5

S = {+√5, -√5}

1 5 1
2014-08-17T17:31:18-03:00
Olá,

faça assim:

2x^2=15-x^2\\
2x^2+x^2=15\\
3x^2=15\\\\
x^2= \dfrac{15}{3}\\\\
x^2=5\\
x=\pm \sqrt{5}\\\\
\large\boxed{\boxed{S=\left\{ \sqrt{5},- \sqrt{5}\right\}}} \\.

Tenha ótimos estudos =))
1 5 1