Finding length of the missing side

Even though this is geometry it comes from my Algebra 2 class.

http://img822.imageshack.us/img822/7...issingside.jpg

I believe that $\displaystyle 2x+3$ is the With so I guess that I have to find the length?

Area : $\displaystyle 2x^2+5x+3$

Area= L*W

Therefore $\displaystyle 2x^2+5x+3= 2x+3$ = Length?

Re: Finding length of the missing side

It should be $\displaystyle 2x^2+5x+3= (2x+3)\times L$ now divide it out.

Re: Finding length of the missing side

You know the length of the rectangle is $\displaystyle 2x+3$ and the area of the rectangle is $\displaystyle 2x^2+5x+3$ that means the breadth of the rectangle has to look like $\displaystyle ax+b$, therefore:

$\displaystyle (2x+3)\cdot(ax+b)=2x^2+5x+3$

Determine $\displaystyle a$ and $\displaystyle b$

Re: Finding length of the missing side

Quote:

Originally Posted by

**pickslides** It should be $\displaystyle 2x^2+5x+3= (2x+3)\times L$ now divide it out.

$\displaystyle 2x^2=L-3x$ ?

Re: Finding length of the missing side

**pickslides** said __divide__ ...

$\displaystyle L = \frac{2x^2+5x+3}{2x+3}$

Re: Finding length of the missing side

Quote:

Originally Posted by

**skeeter** **pickslides** said __divide__ ...

$\displaystyle L = \frac{2x^2+5x+3}{2x+3}$

$\displaystyle L=\frac{2x^2+3x}{1}$ or $\displaystyle 2x^2+3x$

Re: Finding length of the missing side

go learn how to do long division of polynomials ...

Polynomial Long Division

Re: Finding length of the missing side

Quote:

Originally Posted by

**skeeter**

Honestly I think Siron's method will suffice for now.

Re: Finding length of the missing side

Quote:

Originally Posted by

**Quacky** Honestly I think Siron's method will suffice for now.

if you had bothered to check the link, you would have noticed that it also shows the factoring technique.

Re: Finding length of the missing side

Quote:

Originally Posted by

**skeeter** if you had bothered to check the link, you would have noticed that it also shows the factoring technique.

I never denied that. But the subject of the page is on polynomial long division, and I think that's asking the OP to run before they walk. With the UK system, there are about 3 years of teaching between this, which is applying the knowledge of factoring, and polynomial division. (Speechless)

Re: Finding length of the missing side

Quote:

Originally Posted by

**Quacky** Honestly I think Siron's method will suffice for now.

Well, NO method will suffice for now; the OP does not know basics and needs classroom help, period.