Question

If f(x) = 5x2

– 3x + 7, find f(2) – f(–2).
​

Answer 1

Answer:

given f(x)=5x^2-3x+7. ....(i)

we have to find f(2)-f(-2) ....(ii)

first we find f(2)

here x=2 ,put this value in equation (i)

f(2)=5(2)^2-3*2+7

f(2)=5*4-6+7

f(2)=21

similarly put x=-2 in eq (i)

we get f(-2)=33

put both value of f(2) and f(-2) in eq (ii)

f(2)-f(-2)=21-33

=-12

Answer 2

Given,

f(x) = 5x²-3x+7

To find,

The value of f(2)-f(-2).

Solution,

The value of f(2)-f(-2) will be -12.

We can easily solve this problem by following the given steps.

According to the question,

We have the following expression:

f(x) = 5x²-3x+7

Now, we will first find the value of f(2) and then f(-2).

Putting 2 in place of x in the above expression:

f(2) = 5(2)²-3(2)+7

f(2) = 5(4)-6+7

f(2) = 20-6+7

f(2) = 27-6

f(2) = 21

Putting -2 in place of x:

f(-2) = 5(-2)²-3(-2)+7

f(-2) = 5(4)+6+7

f(-2) = 20+6+7

f(-2) = 33

Now, putting the values of f(2) and f(-2) in f(2)-f(-2):

21-33

-12

Hence, the value of f(2)-f(-2) is -12.