Question

Solve 2x + y = 7
x - y = -4

(1, 5)
(-1, 5)
(1, -5)
(-1, -5)

Answer 1

Does the method matter?

Answer 2

Just like the last one, you can solve this problem using substitution or elimination.

Answer 3

If you use elimination, you can add them right away, and eliminate y right off the bat.

Answer 4

elimination

Answer 5

So any clue how to start? Look at my comment above :P

Answer 6

2x + y = 7
- x - y = -4

Answer 7

Add, not subtract

Answer 8

If you add both equations up, you are left with 3x=3. Because the ys are cancelled out. X = 1... Then substitute into the second equation 1-y=-4. y = -5. Done.

Answer 9

2x + y = 7
+ x - y = -4
____________________
3x = 3
x = 1

Answer 10

So i can eliminate answers B & D

Answer 11

That's right! Now substitute x in one of the original equations, and solve for y :)

Answer 12

2(1) + y = 7
2 + y = 7
-2 -2
_____________
y = 5

Answer 13

Good job!

Answer 14

Thank you for helping!!

Answer 15

Np :P