SOLUTION: THE LENGTH OF A RECTANGULAR FIELD IS 20 FT LESS THAN TWICE ITS WIDTH. ITS AREA IS 6000 SQ FT. FIND THE LENGTH AND WIDTH. I KNOW AREA=L TIMES W BUT I CANT QUITE FIGURE OUT HOW

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Question 21456: THE LENGTH OF A RECTANGULAR FIELD IS 20 FT LESS THAN TWICE ITS WIDTH. ITS AREA IS 6000 SQ FT. FIND THE LENGTH AND WIDTH.
I KNOW AREA=L TIMES W
BUT I CANT QUITE FIGURE OUT HOW TO SET IT UP.
LENGTH 2W-20=6000 ??????????
THANKS!
Answer by Paul(988) About Me  (Show Source):
You can put this solution on YOUR website!
(x)(2x-20)=6000
2x%5E2-20x=6000
2x%5E2-20x-6000=0
Use quadratic formula:
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a=2, b=-20, c=-6000
x+=+%28-%28-20%29+%2B-+sqrt%28+%28-20%29%5E2-4%282%29%28-6000%29+%29%29%2F%282%282%29%29+
x+=+%2820%29+%2B-+sqrt%28+400%2B48000+%29%29%2F%284%29 (divide by four)
x+=+%2820%29+%2B-+sqrt%28+48400+%29%29%2F4+ (divide by four)
Add (don't subtract): x=240%2F4
x=60
2(60)-20=100
hence the width is 60ft and the length is 100ft.