- #1

- 8

- 0

**1. The height,length and width of a small box are consecutive intergers with the height being the smallest of the three dimensions. If the length and width are increased by 1 cm each and the height is doubled, then the volume is increased by 120 cm^3. Find the dimensions of he original small box**

**2. v=lwh**

**3. I tried to appoach this two different ways but couldn't get either to work:**

1. h = x

w = x+1

l= x+2

therefore (2x)(x+2)(x+3) = 120

2x^3 + 10x^2+12x-120 = 0

i tried to use the factor theroem to solve the equation but could not get it to work.

p{+-1,+-2,+-3...}

q{+-1,+-2}

p/q {+-1,+-1/2, +-2, +-3, +-3/2...}

I knowthat in order to solve the question, I am going to need to need to find the roots of the polynomial and therefore have to solve for x. The factor theroem indicates that if i plug in p/q into the above given equation, it will equal zero, and i can finish the question. The only problem i am having is determining which p/q value satisfies the equation. Another solution would be to factor, but i tried that and it ended up being..

2x^2(x+5) + 12(x-10) and since there are no more common factors, it cannot be taken any further. As a result, i am pretty sure i have to use the factor theorem, but i can't figure out what p/q value satisfies the equation

So then i tried (2x)(x+2)(x+3)= 120 + (x)(x+1)(x+2)

and got..

x^3+7x^2-10x-120 = 0

and tried to use factor theorem again but couldn't get it to work.

1. h = x

w = x+1

l= x+2

therefore (2x)(x+2)(x+3) = 120

2x^3 + 10x^2+12x-120 = 0

i tried to use the factor theroem to solve the equation but could not get it to work.

p{+-1,+-2,+-3...}

q{+-1,+-2}

p/q {+-1,+-1/2, +-2, +-3, +-3/2...}

I knowthat in order to solve the question, I am going to need to need to find the roots of the polynomial and therefore have to solve for x. The factor theroem indicates that if i plug in p/q into the above given equation, it will equal zero, and i can finish the question. The only problem i am having is determining which p/q value satisfies the equation. Another solution would be to factor, but i tried that and it ended up being..

2x^2(x+5) + 12(x-10) and since there are no more common factors, it cannot be taken any further. As a result, i am pretty sure i have to use the factor theorem, but i can't figure out what p/q value satisfies the equation

So then i tried (2x)(x+2)(x+3)= 120 + (x)(x+1)(x+2)

and got..

x^3+7x^2-10x-120 = 0

and tried to use factor theorem again but couldn't get it to work.

Thanks in advance for the help.

Last edited: