SOLUTION: A rectangle table top has an area f 60 squre feet. LENGTH IS ONE FOOT LESS THAN 4 TIMES THE WIDTH, FIND THE DIMENSIONS.

Algebra ->  Rectangles -> SOLUTION: A rectangle table top has an area f 60 squre feet. LENGTH IS ONE FOOT LESS THAN 4 TIMES THE WIDTH, FIND THE DIMENSIONS.      Log On


   

Question 129955: A rectangle table top has an area f 60 squre feet. LENGTH IS ONE FOOT LESS THAN 4 TIMES THE WIDTH, FIND THE DIMENSIONS.
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Let A=area
Let w=width
Let l=length
A+=+60
A+=+w%2Al
l+=+4w+-+1
A+=+w%2A%284w+-+1
60+=+w%2A%284w+-+1%29
60+=+4w%5E2+-+w
4w%5E2+-+w+-+60+=+0
Use the quadratic formula to find roots
w+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
This is used when equation is in the form
aw%5E2+%2B+bw+%2B+c+=+0
a+=+4
b+=+-1
c+=+-60
w+=+%28-%28-1%29+%2B-+sqrt%28+%28-1%29%5E2-4%2A4%2A%28-60%29+%29%29%2F%282%2A4%29+
w+=+%281+%2B-+sqrt%28+1+%2B+960+%29%29%2F+8+
w+=+%281+%2B-+31%29+%2F+8
w+=+%281+%2B+31%29+%2F+8
w+=+32%2F8
w+=+4
w+=+%281+-+31%29+%2F+8
This gives a negative answer, so I can't use it
l+=+4w+-+1
l+=+4%2A4+-+1
l+=+15
The dimensions are 4 x 15
check answer:
60+=+w%2A%284w+-+1%29
60+=+4%2A%2816+-+1%29
60+=+4%2A15
60+=+60
OK