Answer:
She should have added 18 to 43 rather than subtracted it.
Explanation:
When you are going backwards such as in that problem, you have to do the opposite sign. For example, if it is adding a number, let's say 6, to another number, let's say 4x. So our equation can be 4x + 6 = 18 so I can explain all of the signs.
4x + 6 = 18
- 6 - 6
-----------------
4x = 12
4 times x = 12
/ 4 / 4
x = 3.
I hope this helps for future problems.