the solutions are x = 5 and y = 2.
First, you substitute x as y + 3 in x + y = 7 so you get y + 3 + y = 7
Then, you simplify to get 2y + 3 = 7
Then, 2y = 4, then y = 2
Then, to get x, you substitute y for 2 in x + y = 7 to get x + 2 = 7
then you get x = 5 and y = 2
So x = 5 and y = 2