Question

Carlos solved the equation below for x. His solution is x = 5. What mistake did Carlos make and how could he have verified his solution to know for certain that his answer is correct?

2x - 9 = 19
2x = 10
x = 5

Answer 1

x=5

Explanation:

2 x 13 = 28

28 - 9 = 19

Carlos made the mistake of using the adding symbol instead of the minus because 2 x 5 = 10 and 10 + 9 = 19