Let
and
. Then


and


The expression under the square root can be rewritten as

Recall that

so that

and assuming
and
, we end up with

so that

as required.
Using the x and y intercepts from the graph to find the slope of the line:
slope = (0 - 2) / (4 - 0)
slope = -1/2
Using the point-slope form:
y - 0 = -1/2 (x - 4)
-2y = x - 4
4 = x + 2y
Coefficient of x is 1 and coefficient of y is 2.
Length x width = formula of finding the area of a rectangle
2 3/7 x 2 4/5 = 6 4/5 (6.8)
The area of the rectangle is 6 4/5 / 6.8
3.7x4=14.8. 14.8 cups of sugar