Question

Find the value of the polynomial $5x-4x^2+3$ at
(i) $x=0$
(ii) $x=-1$
(iii) $x=2$

Answer 1

Given polynomial is $5x-4x^2+3$

(i)

If $x=0$

Lets substitute $x=0$ in $5x-4x^2+3$

$=5\left(0\right)-4(0{)}^2+3=0-0+3=3$

Therefore, the value of $5x-4x^2+3$ is $3$, when $x=0$.

(ii)

If $x=-1$

Lets substitute $x=-1$ in $5x-4x^2+3$

$=5(-1)-4(-1{)}^2+3=-5-4+3=-6$

Therefore, the value of $5x-4x^2+3$ is $-6$, when $x=-1$.

(iii)

If $x=2$

Lets substitute $x=2$ in $5x-4x^2+3$

$=5\left(2\right)-4(2{)}^2+3=10-16+3=-3$

Therefore, the value of $5x-4x^2+3$ is $-3$, when $x=2$.