Question 533206
(f-g)(x)=f(x)-g(x) for all x.
For x=2 (f-g)(2)=f(2)-g(2)
You have 2 options to solve your problem:
Option 1 _ You can first work with the x in the functions as they are written to generate the general expression for (f-g)(x), and substitute x=2 later.
Option 2 _ You can calculate f(2) and g(2) first and then do the subtraction with the two numbers.
All that's said above works similarly for (f+g), (fxg) and (f/g)
Sometimes one option is easier or more convenient than the other.
In your case:
Option 1 {{{f(x)=-3x-3}}} {{{g(x)=x^2+2x}}}
{{{(f-g)(x)=-3x-3-(x^2+2x)}}}
{{{(f-g)(x)=-3x-3-x^2-2x}}}
{{{(f-g)(x)=-x^2-5x-3}}}
{{{(f-g)(2)=-2^2-5*2-3}}}
{{{(f-g)(2)=-4-10-3}}}
{{{(f-g)(2)=-17}}}
Option 2
{{{f(2)=-3*2-3}}}
{{{f(2)=-9}}}
{{{g(2)=2^2+2*2}}}
{{{g(2)=4+4}}}
{{{g(2)=8}}}
{{{(f-g)(2)=f(2)-g(2)=-9-8=-17}}}