Question 12272
10y-13=3y+8
We first will +13 to both sides;

10y-13+13=3y+8+13
Now we will subtract 3y from both sides;
10y-3y=3y+21-3y
Now we have the variables on one side:
7y=21
Divide both sides by 7
7y/7=21/7
y=3

Hope you understand =)