Answer:
60
Step-by-step explanation: Simplifying 
15x + 30y = 60 
 
Solving 
15x + 30y = 60 
 
Solving for variable 'x'. 
 
Move all terms containing x to the left, all other terms to the right. 
 
Add '-30y' to each side of the equation. 
15x + 30y + -30y = 60 + -30y 
 
Combine like terms: 30y + -30y = 0 
15x + 0 = 60 + -30y 
15x = 60 + -30y 
 
Divide each side by '15'. 
x = 4 + -2y 
 
Simplifying 
x = 4 + -2y