Graphs are hard: The correct one

Firstly, I'll go through the longer way to do it. (groan)

Graph paper way:

Perhaps the reason why some of you will get it wrong is you don't understand the phrase " $\frac{x}{2}$ - $\frac{y}{3}$ = 5"

That merrily means if you substitute, for example, $x$ for 10, you would also get the coordinates for y as well.

$\frac{10}{2}$ - $\frac{y}{3}$ = 5

5 - $\frac{y}{3}$ = 5

Therefore,

$\frac{y}{3}$ = 0

$y$ = 0

Therefore, your coordinates are (5, 0)

You would continue substituting different things for $x$ , until you had at least 3 or 4 coordinates. Then you would pinpoint them on your graph paper, and connect them, in what should be a straight line. Now you would see the coordinates the question gave you, and see what doesn't fall on the line. You should end up with (7, -5.5) .

Shorter way:

This is a better approach in almost every way. However, it depends on the question being multi-choice.

First of all you would see the formula they give you:

$\frac{x}{2}$ - $\frac{y}{3}$ = 5

Then you see your options:

(-2, -18), (3, -10.5), (7, -5.5)

Then you plug it in:

First option:

(-2, -18)

$\frac{-2}{2}$ - $\frac{-18}{-3}$ = 5

(-1) - (-6) = 5

Therefore, option 1 is on the line.

Second option:

(3, -10.5)

$\frac{3}{2}$ - $\frac{-10.5}{3}$ = 5

1.5 - (-3.5)

= 1.5 + 3.5

= 5

Option 2 is on the line.

Third option:

(7, -5.5)

$\frac{7}{2}$ - $\frac{-5.5}{3}$

= 3.5 - (-1.83333333)

= 3.5 + 1.8333333

=5.3333

Therefore, the answer is (7, -5.5)