x+2y=22 x-y=-2

Question

How do you solve x+2y=22 x-y=-2?

Answer 1

Hey John -- sometimes we may "eyeball" the solution ... since "x" is the same in both ...

 

increasing from -y to 2y raises the total from -2 to 22 ==> 3y's adds 24 ... y=8 ...

 

for x-y to put us "2 below," x must be 6 ==> (6,8) works ... Best regards, sir :)

Answer 2

You can substitute or eliminate a variable.

I will use elimination through subtraction:

 

 

x+2y=22

x-y=-2

----------

3y=24

y=8

 

Substitute 8 into one of the original equations to solve for x:

x+2(8)=22

x=6