Answer: (0,-1) and (1/3,0)
Step-by-step explanation:
can you show me what the math problem is?
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:
100 revolitions
Step-by-step explanation:
180s = 3min
50s = 1min
50 * 2 = 100