2x-4y=8 3x+8y=-2 solve using elimination

2 (2x-4y=8) = 4x-8y = 16

3x+8y=-2

4x-8y=16

3x+8y=-2

the 8s cancel out

4x+3x = 14

7x=14

x=2

2 (2) - 4y = 8

4-4y = 8

-4 - 4

-4y=4

y=-1

x=2

y=-1

(2,-1)

2x+5y=13 multiply both sides by 3

6x + 15y = 39

3x - 4y = 8 multiply both sides by - 2

-6x + 8y = - 16 add the two new equations to each other

(-6x + 8y) + (6x + 15y) = 39 + (-16)

-6x + 6x + 8y + 15y = 39 - 16

0x + 23y = 23

23y = 23

y = 1

2x + 5y = 13 sub in 1 for y

2x + 5 (1) = 13

2x + 5 = 13

2x = 8

x = 4

answer (4,1)

check:

3 (4) - 4 (1) = 8

12 - 4 = 8

8 = 8