Algebra

I'm taking algebra for the 3rd time and I still have no clue what's happening once we get into slope... Specifically, right around slope-intercept form is where I get lost. Like I'm supposed to be taking a quiz right now but I'm very confused as to how the hell I'm supposed to solve 7x-5y=20. Luckily I'm allowed to use a graphing calculator on my computer. Anyway, if anyone know how to do this and has a simple explanation that would be greatly appreciated. :D