Question

If the value of $2x^3-2x^2-x-a$ equals to $5$, when $x=2$, then the value of ${}^{\prime }{a}^{\prime }$ is _________.

• A. $4$
• B. $1$
• C. $3$
• D. $6$

Answer 1

The correct option is B $1$

Given, $f\left(x\right)=2x^3-2x^2-x-a$

When $x=2$

$f\left(2\right)=2\left(2^3\right)-2\left(2^2\right)-2-a=5$

Putting values in given expression

$f\left(2\right)=2\times 2^3-2\times 2^2-2-a=5$

$\Rightarrow 16-8-2-a=5$

$\Rightarrow 6-a=5$

$\Rightarrow a=1$