-4/5 = -16/20, so the new expression is (-16/20)+(3/20)
then, -16 + 3 is -13, so the solution is -13/20
If you'd graph this function, you'd see that it's positive on [-1.5,0], and that it's possible to inscribe 3 rectangles on the intervals [-1.5,-1), (-1,-0.5), (-0.5, 1].
The width of each rect. is 1/2.
The heights of the 3 inscribed rect. are {-2.25+6, -1+6, -.25+6} = {3.75,5,5.75}.
The areas of these 3 inscribed rect. are (1/2)*{3.75,5,5.75}, which come out to:
{1.875, 2.5, 2.875}
Add these three areas together; you sum will represent the approx. area under the given curve on the given interval: 1.875+2.5+2.875 = ?
Answer:
h = hamburgers sold
2h - 72 = 578
2h = 650
2 2
h = 325
There were 72 fewer cheeseburgers sold than hamburgers. That means cheeseburgers = 325 - 72
325 - 72 = 253
253 = cheeseburgers
325 = hamburgers
253 + 325 = 578
Hamburgers = 325
Hope this helps :)