Question

If $f:R\to R,g:R\to R$ are defined by $f\left(x\right)=4x-1,g\left(x\right)=x^3+2,$ then $\left(gof\right)\left(\frac{a+1}{4}\right)=$

• A. $43$
• B. $4a^3-1$
• C. $a^3+2$
• D. $64a^3-8a^2-1$

Answer 1

The correct option is C $a^3+2$

$g\left(f\left(\frac{a+1}{4}\right)\right)=g(4\left(\frac{a+1}{4}\right)-1)$
$=g\left(a\right)$
$=a^3+2$