Question 884052
You are told that b=-2a+3
f(x)=5a+3b=11
g(x)=-2a+3

{{{(fog)(x)=5a+3(-2a+3)=11}}}

So in your first equation, substitute -2a+3 for b.


{{{5a+3b=11}}}
{{{5a+3(-2a+3)=11}}}
{{{5a-6a+9=11}}}
{{{-a+9=11}}}
{{{-a=2}}}
{{{a=-2}}}

Now sub your found value of a into the equation to find b.

{{{b=-2a+3}}}
{{{b=-2(-2)+3}}}
{{{b=4+3}}}
{{{b=7}}}

You can check this by substituting your values for a and b back into your first equation

{{{5a+3b=11}}}
{{{5(-2)+3(7)=11}}}
{{{-10+21=11}}}
{{{11=11}}}