SOLUTION: The area of the base of a rectangular desk telephone is 780 square centimeters. The length of the rectangular telephone is 4 centimeters longer than its width. What is the length a

Algebra ->  Equations -> SOLUTION: The area of the base of a rectangular desk telephone is 780 square centimeters. The length of the rectangular telephone is 4 centimeters longer than its width. What is the length a      Log On


   



Question 664406: The area of the base of a rectangular desk telephone is 780 square centimeters. The length of the rectangular telephone is 4 centimeters longer than its width. What is the length and width?



Answer by ReadingBoosters(3246) About Me  (Show Source):
You can put this solution on YOUR website!
Given
a = 780 cm%5E2, which is (l)(w)
l = w+4
...
Plug and Play!
(w+4)(w) = 780
Distribute the w
w%5E2 + 4w = 780
create the quadratic
w%5E2 + 4w - 780 = 0
(w- )(w+ ) mixed sign due to the + 4 and - 780
Find multiple of 780 that subtracts to 4: 30,26
(w-26)(w+30)
w-26=0, so w=26
w+30=0, so w=-30
Width cannot be negative, so the width is 26 cm
...
l = 26 + 4 = 30 cm is the length
..
Check
a = 26(30) = 780
....................
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