Factor the Expression 3y + 6y: Finding the Greatest Common Factor

We start with the expression $3y + 6y$.

First, we notice that both terms share a common factor of $y$.

So, we factor out $y$ from each term:

$3y = y\cdot 3$ and $6y = y\cdot 6$.

We can also see that $6$ can be factored to $2\cdot3$.
Now when we look at the expression we can see that both $y$ and $3$ are the common factor: $\blue3\cdot \orange y+2\cdot\blue 3\cdot \orange y$

This allows us to rewrite the expression as $3y\left(1+2\right)$, as nothing is left from the first term, and so we keep there a $1$, and $2$ is left from the second term.

Thus, the factored form is $3y\left(1+2\right)$