Area = width * height
since the window is 20 inches higher than the width:
width +20 = height
640 = width * width+20
640 = width^2 +20*width
width^2 +20*width - 640 = 0
width = 17.203
**********************************************************
Double Check
if width = 17.203 then height = 37.203
area = 17.203 * 37.203 = 640 square inches Correct!!
-7.14 should be your answer!
2744 is the answer. can be written as 14^3 just in case you need to know that.
3.75* .92= $3.45
2.1* 1.10= $2.31
$3.45
+ $2.31
_______
$5.76