Question

I am thinking of

two numbers.
When I add them
I get 15.
When I subtract
them I get 3.
What are the two
numbers?

Answer 1

9 and 6

Explanation:

Write down the system.

The two numbers are x and y.

We are therefore given:

x+y=15

x-y=3

I will solve this for elimination since it is already setup for it.

I will add the columns since both equations are in the same form.

2x+0y=18

2x =18

Divide both sides by 2:

x =18/2

Simplify:

x =9

So if x+y=15 and x=9, then y=6.

The two numbers are 9 and 6.

Test:

9+6=15

9-6=3