How would this graph look like?

Question

a+b = 10

3a+2b = 40

Answer 1

these are two equations, solution is a single value of a and b.

If you graphed the solution of each equation individually, with a on x axis and b on y axis, then each would look like a line (just rearrange to get standard "y=mx+c" form of a line).  So, you have two lines, and they intersect at a point -- that point satisfies both equations, and thus is your solution.  

I'm not sure if this is what you're looking for .....