Question

1. 21x-3y=0
y=7x

2. -13x+y=-8
26x-2y=13

3. -2x-6y=-14
x+3y=7

4. 4x+2y=6
6x+3y=9

5. x+9y=-36
x+9y=-54

6. 3x-8y=32
7x-4y=-28