Find the value of the polynomial $ 5 x-4 x^{2}+3 $ at
(i) $ x=0 $
(ii) $ x=-1 $
(iii) $ x=2 $
To do:
We have to find the value of the polynomial \( 5 x-4 x^{2}+3 \) at
(i) \( x=0 \)
(ii) \( x=-1 \)
(iii) \( x=2 \)
Solution:
To find the value of the polynomial $f(x)$ at $x=a$, we have to substitute $x=a$ in $f(x)$.
Let $f(x)=5 x-4 x^{2}+3$
Therefore,
(i) When $x=0$,
$f(0) = 5 (0)-4 (0)^{2}+3$
$= 0-4 (0)+3$
$= 0-0 + 3$
$= 3$
Hence, the value of the polynomial \( 5 x-4 x^{2}+3 \) at \( x=0 \) is $3$.
(ii) When $x=-1$,
$f(-1) = 5 (-1)-4 (-1)^{2}+3$
$= -5-4 (1)+3$
$= -5-4 + 3$
$= -9+3$
$=-6$
Hence, the value of the polynomial \( 5 x-4 x^{2}+3 \) at \( x=-1 \) is $-6$.
(iii) When $x=2$,
$f(2) = 5 (2)-4 (2)^{2}+3$
$= 10-4 (4)+3$
$= 10-16 + 3$
$= 13-16$
$=-3$
Hence, the value of the polynomial \( 5 x-4 x^{2}+3 \) at \( x=2 \) is $-3$.
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