Find the LCM 5x^3y and 15x^2y^2

Since ${\displaystyle 5x^{3}y,15x^2{y}^2}$ contain both numbers and variables, there are two steps to find the LCM. Find LCM for the numeric part ${\displaystyle 5,15}$ then find LCM for the variable part ${\displaystyle x^3,y^1,x^2,y^2}$.

The LCM is the smallest positive number that all of the numbers divide into evenly.

1. List the prime factors of each number.

2. Multiply each factor the greatest number of times it occurs in either number.

Since ${\displaystyle 5}$ has no factors besides ${\displaystyle 1}$ and ${\displaystyle 5}$.

${\displaystyle 5}$ is a prime number

${\displaystyle 15}$ has factors of ${\displaystyle 3}$ and ${\displaystyle 5}$.

Multiply ${\displaystyle 3}$ by ${\displaystyle 5}$.

The factors for ${\displaystyle x^3}$ are ${\displaystyle x\cdot x\cdot x}$, which is ${\displaystyle x}$ multiplied by each other ${\displaystyle 3}$ times.

${\displaystyle x}$ occurs ${\displaystyle 3}$ times.

The factor for ${\displaystyle y^1}$ is ${\displaystyle y}$ itself.

${\displaystyle y}$ occurs ${\displaystyle 1}$ time.

The factors for ${\displaystyle x^2}$ are ${\displaystyle x\cdot x}$, which is ${\displaystyle x}$ multiplied by each other ${\displaystyle 2}$ times.

${\displaystyle x}$ occurs ${\displaystyle 2}$ times.

The factors for ${\displaystyle y^2}$ are ${\displaystyle y\cdot y}$, which is ${\displaystyle y}$ multiplied by each other ${\displaystyle 2}$ times.

${\displaystyle y}$ occurs ${\displaystyle 2}$ times.

The LCM of ${\displaystyle x^3,y^1,x^2,y^2}$ is the result of multiplying all prime factors the greatest number of times they occur in either term.