Question

If $f\left(x\right)=x^2+1$ and $f\left(a\right)=26$, then find $a$.

• A. $5$
• B. 4
• C. 6
• D. 8

Answer 1

The correct option is A $5$

Given,
$f\left(x\right)=x^2+1$
$f\left(a\right)=26$
Putting $a$ in place of $x$, we get
$f\left(a\right)=a^2+1=26$
$\Rightarrow a^2+1=26$
$\Rightarrow a^2=25$
$\Rightarrow a=5$