answer: she is right that y = 29, but step three should be addition property of equality.
work: let's see how she worked to isolate y. she started by subtracting 2y from both sides, so so far she is correct. after that, she added 84 to both sides, and again that is a correct step, but her proof is wrong, since you are adding and not subtracting 84, it's the addition property of equality. lastly, she divided 145 by and correctly got 29. so yes, she is correct.
