a few more math problem
solve each system by elimination
1. 7x+y=10
-7x-10y=26

2. 4x-2y=-14
3x-2y=-14

3. 6x+2y=20
-3x+3y=-30

4. -5x+4y=-3
-9x-4=-30

5. -9x+6y=27
-x+3y=10

6. 5x+y=-12
5x-7y=4