I have no graph paper so I can’t help you with the graph.

Remember that in the form Y = mX + c,

Y can only contain mixture of x and/or y (this includes their lg, ln, squares, square roots and so on), and must not contain unknown variables such as a and b

X can only contain mixture of x and/or y (this includes their lg, ln, squares, square roots and so on), and must not contain unknown variables such as a and b

m can only contain unknown variables such as a and b, and must never contain the main variables x and/or y

c can only contain unknown variables such as a and b, and must never contain the main variables x and/or y

An easy way is to do this.

When writing

something = something + something,

there are three terms correct? (Y, mX and c)

Exactly one of the three terms must not contain any x or y in any form.

It is possible for Y to contain x only, and for X to contain y only, in a minority of instances.