Question

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

Answer 1

Answer:

(3,-1)

Step-by-step 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 :)