1. ## Writing Equations - Quadratics 2

The area of a square is triple by adding 10 cm to one dimension and 12 cm to the other. Determine the side length of the square.

My attempt:

area = (l)(w)

3x^2 = 10x + 12x

This is all I got done, I am pretty sure I am wrong though...

2. ## Re: Writing Equations - Quadratics 2

If you let the side of the square be l, then the area of the square is l^2. If you add 10 to one dimension and 12 to the other, then the new area should be given by (l+10)(l+12)=new area (why?). Since you know that the new area is three times the original, you can solve for the length of the square.

3. ## Re: Writing Equations - Quadratics 2

Originally Posted by Mathnood768
The area of a square is triple by adding 10 cm to one dimension and 12 cm to the other. Determine the side length of the square.

My attempt:

area = (l)(w)

3x^2 = 10x + 12x

This is all I got done, I am pretty sure I am wrong though...
Area(initial) = (l)(w)

3 x Area = (l + 12)(w +10) , go from this now...

dokrbb

4. ## Re: Writing Equations - Quadratics 2

I still do not know what to do after that, I am really bad at math..

5. ## Re: Writing Equations - Quadratics 2

Again, you get 3x^2=(x+12)(x+10)

3x^2=x^2+22x+120

2x^2-22x-120=0

x^2-11x-60=0
(x-15)(x+4)=0

Two solutions. Choose the one that makes sense. ( one is negative and a square cannot have a negative side)

6. ## Re: Writing Equations - Quadratics 2

Thank you! This makes sense to me now. I am slowly getting better at these word problems.