Answer:
y=9
Step-by-step explanation:
Isolate the variable by dividing each side by factors that dont contain the variables
move variable to left side and change its sign
42-7y+3y=6 collect like terms
-7y +3y=6-42
-4y=6-42
-4y=-36 divide both sides of the equation by -4
y=9
hope that helps :)