Question

Solve the following system of equations by graphing.

x – y = 7
x – y = 5

What is the solution?

Answer 1

Graph it!

Answer 2

No need to graph.

If you let z = x-y, then you go from

x-y=7
x-y=5

to

z = 7
z = 5

Answer 3

z is some (single) number...but it can't be 2 numbers at the same time

Answer 4

So that last statement of

z = 7
z = 5

is impossible