# Please help me set up rational zero word prorblem. . .

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• Feb 27th 2009, 03:53 PM
runner940
Please help me set up rational zero word prorblem. . .
Here is my word problem:

SWIMMING POOL You are designing a rectangular swimming pool that is to be set into the ground. The width of the pool is 5 feet more than the depth, and the length is 35 feet more than the depth. The pool holds 2000 cubic feet of water. What are the dimensions of the pool?

*Please help me to set up, I am having trouble even starting this problem. . .(Thinking)
• Feb 27th 2009, 03:59 PM
e^(i*pi)
Quote:

Originally Posted by runner940
Here is my word problem:

SWIMMING POOL You are designing a rectangular swimming pool that is to be set into the ground. The width of the pool is 5 feet more than the depth, and the length is 35 feet more than the depth. The pool holds 2000 cubic feet of water. What are the dimensions of the pool?

*Please help me to set up, I am having trouble even starting this problem. . .(Thinking)

Write down what we know:

w = d+5
L = d+35
V = wLd = 2000

$2000 = d(d+5)(d+35)$, $2000 = (d^2+35)(d+5) = d^3 +5d^2 + 35d + 175$ and so $d^3 + 5d^2 + 35d - 1825 = 0$

Solve the cubic for d and then work out w and L from your value(s) of d