Answer:
The step 4 is not what he should have done. But the wrong is step 5, because if he added -2x both sides, it would give the following equation:

and not 
Note that in step 4 he should have added 2x and not -2x to both sides, but we still have the equality. The problem is that step 5 is totally wrong.
I don't know what answer is expected to this question, but I would mark step 5, because this is mathematically wrong.
Solving the equation

Using distribution

Add
both sides


Add 12 both sides

Divide both sides by 5

Answer:
A) 991=43x+475
B) 12 hours
Step-by-step explanation:
Answer:
b) change the places of the numbers in the numerator and the denominator for the second fraction
Step-by-step explanation:
In the phrase "keep change flip":
You "keep" the first fraction.
"Change" the division sign into a multiplication sign.
"Flip" (or switch) the places of the numerator and denominator in the second fraction.
Example:
÷ 

Hope this helps.
360 blinks / 30 minutes = 12 blinks per minute
12 blinks per minute x 9 minutes = 108 blinks
Answer: 108