Question

If ƒ (x ) = 3x2 - x, find ƒ (-2).

I literally have no idea what I'm looking at....maybe I should've paid better attention leading up to the test.

Answer 1

14

Explanation:

f(x) = 3x² - x

To find f(-2), substitute -2 for x into the function f.

• f(-2) = 3(-2)² - (-2)

Now, use PEMDAS to evaluate the function.

Start by evaluating the exponent.

• f(-2) = 3(4) - (-2)

Next, multiply 3 and 4 and -2 by -1.

• f(-2) = 12 + 2

Add the two terms together.

• f(-2) = 14

The correct answer is f(-2) = 14.

Answer 2

f(x)=3x^2-x

`\\ \rm\longmapsto f(-2)`

`\\ \rm\longmapsto 3(-2)^2-(-2)`

`\\ \rm\longmapsto 3(4)-(-2)`

`\\ \rm\longmapsto 12-(-2)`

`\\ \rm\longmapsto 12+2`

`\\ \rm\longmapsto 14`