Question

Solve by addition method
3x+y=8
2x-y=7

Answer 1

(3,-1)

Explanation:

So we have the system of equations:

`3x+y=8\\2x-y=7`

As directed, add straight down. The y-variable will cancel:

`5x=15`

Now, divide both sides by 5. The left cancels:

`x=3`

So x is 3.

Now, substitute 3 for x in either of the equations:

`3x+y=8`

Substitute 3 for x:

`3(3)+y=8`

Multiply:

`9+y=8`

Subtract 9 from both sides:

`y=-1`

So, our answer is: x=3, y=-1 or (3,-1).

And we are done :)