Answer:
x=15
Explanation:
Given: The equation, 3x – y = 18
We need to find the value of x at y=27 
So, we put y=27 into the equation and solve for x 
3x - 27 = 18 
Add 27 both sides (Addition property of equality) 
3x -27 + 27 = 27 + 18 
 3x = 45
Divide both sides by 3 (Division property of equality) 
 x = 15
Hence, The value of x is 15