Find the LCD 3/(7b) , 5/(3c) , 11/(21bc)

For each instance of a variable included in the terms, compare the power of the variable in term one with the power of the variable in term two. Return the variable with the larger exponent.

For variable ${\displaystyle b}$, ${\displaystyle b^1}$ has a greater power than ${\displaystyle b^0}$, so keep ${\displaystyle b^1}$.

Variable: ${\displaystyle c}$

Find the values of the numerical part of each term. Select the largest one, which in this case is ${\displaystyle 7}$. Multiply them together to get the current total. In this case, the current total is ${\displaystyle 21}$.

Multiply the numeric part of the denominators together.

Multiply the numeric part of the denominators together.

Check each value in the numerical part of each term against the current total. Since the current total is evenly divisible, return it. That is the least common denominator of the numerical part of the fraction.

Multiply all saved numbers and variables and their powers together: