Question 74313
When you say 4g you're saying 4*g(x) which means that you're going to multiply 4 by the output g(x). So if I plug in x=0 for g(x) I get 
{{{g(0)= 7-3(0)}}}
{{{g(0)=7}}}
So 4*g(0)=4(7)=28.
Now we're going to do this in terms of x
{{{4g(x)-5f(x)=4(7-3x)-5(-x/5)}}}
{{{4g(x)-5f(x)=28-12x+(5x/5)}}}
{{{4g(x)-5f(x)=28-12x+x}}}
{{{4g(x)-5f(x)=28-11x}}}
So 4 times g(x) plus 5 times f(x) is 28 minus 11x. I hope this makes sense.