Find two numbers such that their sum is 2 and their difference is 4

Question

x+y=2

x-y= 4

Answer 1

x + y = 2

x - y = 4

2x = 6, add the two equations

x = 3

Can you determine the value of y?

Answer 2

This is a simple one requiring substitution

I would start by solving for x in your first equation:

x+y=2

-y -y

----------

x=2-y

now substitute that into your second equation

x-y=4

(2-y)-y=4 <--see how (2-y) replaced the x?

now solve for y

2-2y=4

-2y=2

y=-1

now go back and substitute -1 for your y in either equation

x+(-1)=2

x=3

Make sure your values work in both equations!

x+y=2 --> 3+(-1) = 2 check

x-y=4 --> 3-(-1) = 4 check

All the best

Lori