Question

if f(x) 5x^2-4x+5 find f(1)+ f(-1)+ f(0)

Answer 1

f (1)=5x^2-4x+5 = 5 (1)^2-4 (1)+5=6
f (-1)=5 (-1)^2-4 (-1)+5=14
f (0)=0+0+5
therfore f (1)+f (-1)+f (0)=6+14+5=25

Answer 2

Given:

$f(x) = 5 {x}^{2} - 4x + 5$

To find:

f(1) + f(-1) + f(0)

Solution:

As given,

we have a quadratic equation

$f(x) = 5 {x}^{2} - 4x + 5$

Now,

On putting x = 1,

f(1)

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

$= 5 - 4 + 5$

$= 6 \: \: (i)$

Similarly,

on putting x = -1

f(-1)

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

$= 5 + 4 + 5$

$= 14 \: \: (ii)$

and

x = 0

f(0)

$= 5( {0}^{2} ) - 4(0) + 5$

$= 5 \: \: \: (iii)$

On adding (i), (ii) and (iii), we get

f(1) + f(-1) + f(0) = 6 + 14 + 5 = 25

Hence, the value of f(1) + f(-1) + f(0) is 25.