Question

If f(x) = 2x2 + 1, what is f(x) when x = 3? a.1 b.7 c.13 d.19

Answer 1

The value of f(x) =
`2x^2 + 1` when x=3 is 19, hence the correct option is ‘d’.

Solution:

A two degree polynomial equation is given in the question.

The equation is:

`F(x)=2 x^(2)+1`

We need to find the value of f(x) when the value of x is 3.

To solve a question like this we have to substitute the given value of x in the given equation and then simplify it.

Now let's substitute the value of x in the given equation.

`F(x)=2(3)^(2)+1`

First we square the number 3 and then multiply it with 2 and then add 1.

This is done because of the BODMAS rule, in which multiplication is given higher preference as compared to addition.

On solving the equation we get,

F(x)=2×9+1

F(x)=18+1

F(x)=19.

Therefore the value of f(x) when x=3 is 19.

Hence the correct option is ‘d’.