The sum of 2 numbers 13 and the difference of 3

Question

What is the answer? Help wanted!

Answer 1

x+y=13

x-y=3

x=13-y

x=3+y

13-y=3+y

13=3+y+y

13-3=y+y

10=2y

5=y

x-y=3

x-5=3

x=3+5=8

x=8

y=5

Answer 2

x+y=13

x-y = 3 add to eliminate y

2x = 20

x = 20/2 = 10

y=13-10 = 3

13-10=3