Here is a picture of a math problem.

X=-2y

1. ( , 0);  
2. (9, );  
3. ( , -2); 

1. (0, 0), as any number multiplied by 0 is 0.
2. x=9, so 9=-2y, y=-4.5 - (9, -4.5)
3. y=-2, so -2y=(-2)*(-2)=4=x - (4, -2)

Solutions: (0, 0), (9, -4.5), (4, -2).