What did they do wrong? If u don’t know don’t answer and if ur right I’ll give u brainliest

They subtracted 5 on both sides of the equation. They were suppose to add 5 on both sides of the equation for it to cancel out each other. If you need any further explanation, please ask me :)
Correct version:
5y + (-5) = 10
+5 +5 add 5 to both sides, 5's will cancel out on left side.
___________
5y 15
__ = __ divide 5 on both sides, 5's will cancel out on left side.
5 5
y = 3, final answer
Answer:
its the first part the (-5) -5 is supposed to be (-5) +5
Step-by-step explanation:
so the equation is 5y=15
then you divide 5y/5 is y so then you 15/5 is 3
so the answer is y=3