We have been given the steps to solve the equation as
Step 1: 2x = 18
Step 2: x = 18 − 2
Step 3: x = 16
There is an error in step 2.
We have 
x is in multiplication with 2. So in order to get rid of 2 from the left hand side, we perform opposite operation of multiplication i.e. division.
So we must divide both sides by 2.
Therefore, A is the correct option.
A) She did not divide 18 by 2.
Answer:
The answer would be 11 1/3 ft sqared
I set x-3 and 3x-13 equal to each other and then got x equal to 5. So, I believe the correct answer would be C.) 5
4/5x - 4/10 = 2/20...multiply everything by common denominator 20
16x - 8 = 2
16x = 2 + 8
16x = 10
x = 10/16 which reduces to 5/8 <=