She subtracted 5x instead of distributing. This is incorrect, because since it is in ( ), it has to be multiplied by 3.
Correct: 3(5x + 9) = 15x + 27
12x + 3 = 15x + 27
Noah:
Added 15x instead of subtracting. This is incorrect, because to combine like terms on each side you would add a negative number and subtract a positive number.
the first choice has a negative 7 and the second choice has a negative 161 these are both negatives in different places which cause a different reaction
