The actual correct answer is:
x = 78
Explanation:
Although the explanation above is correct, the answer is wrong. It's not 66 because you are subtracting 6 from x. This means x needs to be 6 above 72.
Here is my step-by-step solution:
x - 6 = 72 <-- Given; Corrected Equation
x - 6 + 6 = 72 + 6 <-- Addition Property of Equality
x = 78 <-- Result from Solution