Question

For the function defind as $f\left(x\right)=\frac{x^2}{4}-11$, find the value of $x$ if $f\left(x\right)=-7$.

• A. $-4$
• B. $10$
• C. $38$
• D. $100$

Answer 1

The correct option is A $-4$

We have $f\left(x\right)=\frac{x^2}{4}-11$

Now given equation is,

$\frac{x^2}{4}-11=-7$

$\Rightarrow \frac{x^2}{4}=-7+11=4$

$\Rightarrow x^2=4\times 4=16$

$\Rightarrow x=\pm \sqrt{16}=\pm 4$