Question

Can anybody tell me the step by step?

Answer 1

For instance, X= 8 and Y=4 it doesn’t matter unless given what number you use X can be any number 1-12 as long as if you add y number it can be = to 122

Answer 2

I'm assuming you want to solve for each variable. There isn't much to do for your question.

We want x:

x + y = 12

Subtract y to get x alone.

x = 12-y

We want y:

x+y=12

Subtract x to get y alone.

y = 12-x