Answer:
is this an essay question?
False, that is the Pythagorean theorem.
Just saying this but don't go to that store! The answer, by the way is $1494
Sure... a good example of that is when you have non-linear expressions in the system, like say for example a linear and a quadratic, like y = 4x and y = x².
recall that for a system of equations, where the graph of both equations intersect, is the solutions, check the picture below.