What is the system of equation of:
1/2x+-2/3y=4
2x+1/3y=7
If you mean what is the solution to the system of equations, just start working things through. I find it easy to get rid of the fractions first:
1/2 x - 2/3 y = 4
2x + 1/3 y = 7
multiply to get
3x - 4y = 24
6x + y = 21
Now get rid of one of the variables, say y.
3x - 4y = 24
24x + 4y = 84
Now add the two equations to get
27x = 108
x = 4
Now you can get y = -3
Do your others the same way. If you get stuck, show what work you have.