Solve by graphing
y=-1/4x +4
y=7/4x -4
each is a straight line, so pick any two points for each line
In this case, pick multiples of 4 for your x choice to avoid fractions
e.g. let x = 4, then y = 3 ---> (4,3)
let x = 8, then y = 2 ----> (8,2)
for the 2nd,
let x = 4, then y = 3 ---> (4,3)
let x = 8, then y = 10 ---> (8,10)
your graph should look like this:
http://www.wolframalpha.com/input/?i=plot+y%3D-1%2F4x+%2B4%2C++y%3D7%2F4x+-4
looks like the solution is (4,3), (which I just happened to have chosen by sheer luck)
I just added a domain of 0<x<10 to take a closer look
http://www.wolframalpha.com/input/?i=plot+y%3D-1%2F4x+%2B4%2C++y%3D7%2F4x+-4+%2C+0+%3Cx%3C10