Odyssey Ware Geometry help: Unit 9 Coordinate Geometry: Equations of Lines

I have a week to finish this and I've been stuck forever. Someone PLEASE help me...
Indicate the equation of the given line in standard form.

The line containing the median of the trapezoid whose vertices are R(-1, 5) , S(1, 8), T(7, -2), and U(2, 0).

Sketch the points so that you can predict which sides are the bases.

you will need:
Slope formula: m= (y2-y1)/(x2-x1)
Midpoint formula: [ (x1+x2)/2, (y1+y2)/2]

You can tell by finding the slopes of the sides, that RU and ST are the bases because they have the same slope: m= -5/3

The median is parallel to the bases, so will have m= -5/3
The median passes through the midpoints of the legs.

The midpoint of RS is (0, 13/2) . this is nice because it is also the y intercept of the median.
So b = 13/2

Y= (-5/3)x + 13/2

In standard form: 10x+ 6y= 39

I hope this helps!

Midpoint of RS is (0,6.5)

Midpoint of TU is (4.5,-1)

So, you want the line thru those two points...

Slope = (6.5-(-1)) / (0 - 4.5) = 7.5/(-4.5) = -5/3

Y=mx+b <<< use to solve for b
6.5=(-5/3)(0) + b
b = 6.5

So, y = (-5/3)x + 6.5
Multiply by 6 and RE-arrange to get to standard form

10x + 6y = 39

How do you define "Median of a Trapezoid" ?