Question

What is the value of x in the equation x – y = 30, when y = 15?

Answer 1

x+y=30.....(1) and x-y=2......(2) so(1)+(2)......x+y+x-y=30+2 so 2x=32...x=16 now apply x=16 in (1) so we get......16+y=30 so .......y=14

Answer 2

Plug in y.

x-15= 30

Add 15 to the other side.

x= 45

I hope this helps!
~kaikers