Question

The difference of two numbers is 3. Their sum is 13. Write a pair of simultaneous equations in x and y to represent this information.

Answer 1

x + y = 13

x - 3 = y

or

x + y = 13

y - 3 = x

Answer 2

x-y=3

x+y=13

2x=16

x=16/2

x=8

x+y=13

8+y=13

y=13-8

y=5