Solve the top equation for x and then substitute that into the bottom equation and solve for y:
Top equation: subtract 4 from both sides to get x = y - 4
Substitution and simplify:
y = 4(y - 4) - 10
y = 4y - 16 - 10
y = 4y - 26
-3y = -26
y = 26/3 or 8 1/3 or 8.333 (those are all the same but in different forms)
