How do i rewrite an equation so that y is a function of x? for example how do i rewrite : 3x + 5y = 7 ?

If you would like to rewrite the equation 3*x + 5*y = 7 so that y is a function of x, you can do this using the next few steps:

3*x + 5*y = 7
5*y = 7 - 3*x    /5
y = (7 - 3*x) / 5
y = 7/5 - 3/5*x

The result is y = 7/5 - 3/5*x.

Any pictures or something i need more info

The answer would be 4x+3