Roots of Polynomial Equations wordproblem-find the dimension

[wind]

A cereal box is a rectangular prism with a volume of 2500 cm^3. The box is 4 times as wide as it is deep, and 5 cm taller than it is wide. What are the dimensions of the box?

V= 2500

The box is 4 times as wide as it is deep so...

4d=w

5 cm taller than it is wide

w + 5 = T

V=(l)(w)(h)
2500=(l)(4d)(4d+5)
2500=(l)(16d^2 + 20d)

I don't know what to do next because there is two variables, l and d, I don't even know if I am doing this right. :?

Can someone please help me? Thanks

 

[skeeter]

A cereal box is a rectangular prism with a volume of 2500 cm^3. The box is 4 times as wide as it is deep, and 5 cm taller than it is wide. What are the dimensions of the box?

w = 4d
h = w+5

V = whd

V = w(w+5)(w/4)

2500 = (w³ + 5w²)/4

solve for w

 

[wind]

ok, thanks I mixed up lenght and height