Answer:
x = 63
Explanation:
Simplifying 
x + -18 = 45 
 Reorder the terms: 
-18 + x = 45 
 Solving 
-18 + x = 45 
 Solving for variable 'x'. 
 Move all terms containing x to the left, all other terms to the right. 
 Add '18' to each side of the equation. 
-18 + 18 + x = 45 + 18 
 Combine like terms: -18 + 18 = 0 
0 + x = 45 + 18 
x = 45 + 18 
 Combine like terms: 45 + 18 = 63 
x = 63 
 Simplifying 
x = 63