You substitute y with -6 and get the equation 4x+5(-6)=52 from there you solve.
First you do 5 times -6 and get -30 and drop everything else to get 4x+(-30)=52
Second you take the -30 and add 30 to each side to leave you with 4x=82
Third you divide both sides by 4 and that leaves you with x=20.5
So your answer is 20.5 or 20[tex] \frac{1}{2} [/tex]