# Equation help - LCD with variables

#### Naldo

Hi there,

Many thanks in advance for the help.

Here is the equation I am struggling to solve:

110 = 1/(1+r) x 32.1/r

How I solve for "r", or perhaps find an LCD with these denominators?

Thanks so much,
Naldo

#### skeeter

MHF Helper
110 = 1/(1+r) x 32.1/r
assuming the "x" meant multiplication ...

$$\displaystyle 110 = \frac{32.1}{r(r+1)}$$

$$\displaystyle r(r+1) = \frac{32.1}{110}$$

$$\displaystyle r^2 + r - \frac{32.1}{110} = 0$$

recommend using the quadratic formula ...

#### Naldo

Thank you so much for the help!

Best!