If if x+y=10, find the value of y when x=3

Let me help you,

for this question, you know what is x and you wanna find the y.
So the only thing you should do is to put 3 for x and solve the equation:
3 + y = 10 
y = 10 -3
y = 7 

Hava great one!

Hey, Hardq!
The problem already gave us x. So we plug it in.
3+y=10
We now want to make the variable by itself, so we subtract 3 to the other side.
y=10-3
Simple Math
y=7
I hope this helps;)

This law is sometimes called the grouping property. as you can see, regardless of how the numbers are grouped, the answer is still 13. the associative law of multiplication is similar to the same law for addition. it says that no matter how you group numbers you are multiplying together, you will get the same answer.