​ The roots of the equation √(2x^2 + 9) = 9 are ​

Question

The roots of the equation \(\sqrt{2x^2+9}\) = 9 are 

A) x = 0 

B) x = ± 6 

C) x = 6 

D) x = -6

Answer 1

Correct option is (B) x = ± 6

Given equation is \(\sqrt{2x^2+9}=9\)

\(\Rightarrow2x^2+9=9^2=81\)

\(\Rightarrow2x^2=81-9=72\)

\(\Rightarrow x^2=\frac{72}2=36\)

\(\Rightarrow\) \(x=\pm\,\,6\)

Hence, the roots of given equation are \(\pm\,\,6.\)

Answer 2

Correct option is B) x = ± 6