Hi zelda,

the midpoint formula ought to work easily enough.

You can simply say....

the x co-ordinate of the midpoint is halfway between the x co-ordinates

of the points on the line.

So -2 is halfway between 7 and another x.

-2 is 9 away from 7.

The other value 9 away from -2 is -11.

So -2 is halfway between -11 and 9.

Also 4 is halfway between 10 and -2

The other point is (-11,-2).

Using the midpoint formula, which is

"the x midpoint is the average of the x values"

"the y midpoint is the average of the y values".