Which is f (5) for the function - 2x2 + 2x - 3?

Given:

f (5) for the function - 2x² + 2x - 3

usually the value enclosed in a parenthesis in a function is the value of x.

f (x) = - 2x² + 2x - 3

So if x = 5; then, we simply substitute x by its value

f (5) = - 2 (5²) + 2 (5) - 3

f (5) = - 2 (25) + 10 - 3

f (5) = - 50 + 10 - 3

f (5) = 10 - 50 - 3

f (5) = 10 - 53

f (5) = - 43