Question 3204
2x + 2y = 25 and you know that y = 3
you simply put this 3 in the equation where y stands:

2x + 2*3 = 25
now bring everything that is not x to the other side:
2x = 25 - 6 = 19
so x = 19/2 = 9.5

is this what you meant?

Greets,
gurdebeke_pieter@hotmail.com for questions