Question

how to find f(-2) when f(x) = -2x – 3?

Answer 1

You can use synthetic substitution if you wanted. Or you can just plug -2 into the equation.
This is because f(x)=-2x-3
The x in the f(x) is the same as the x in -2x-3
Therefore all we have to do is put -2 in for x and solve.
-2(-2)-3
4-3
f(-2)=1

Synthetic substitution is also valid here

Essentiallly, you put the f(-2) into there, drop the first coefficient down, multiply the -2 by the -2, and then put that under the -3. You add -3 and 4 and you get 1.