Given f (x) = 3x^3 - 4x^2 + x - 1 , what is f (2) ?

Question

I really don't understand this, please explain!

Answer 1

f(x) = 3x^3 -4x^2 + x -1

f(2) = 3(2)^3 -4(2)^2 +2 -1 = 3(8) -4(4) +3-1 = 24-16 +1 = 8+1 = 9

f(2) = 9

Answer 2

Hi! So you have to plug in the number 2 into the function everywhere that you see an x. The equation that you need to solve becomes:

3(2^3)-4(2^2)+2-1

Then, we can use PEMDAS to remember the order of operations and solve. So, we have to start with the exponents. The equation becomes:

3(8)-4(4)+2-1

Next, we can do multiplication.

24-16+2-1

Now, we do addition and subtraction from left to right:

8+2-1

10-1

9

f(2) = 9