With a Number Inside

The factors inside the parentheses do not have to be letters. $\left(3y\right)^{2}$ has two factors inside, 3 and $y$, and each one takes the power: $3^{2}y^{2}$. Then work out the number's power: $9y^{2}$.

Squaring $3y$ squares the 3 as well as the $y$. So $\left(3y\right)^{2}$ is $9y^{2}$, never $3y^{2}$. The example also shows why doubling the side of a square makes its area four times bigger: the new side $2s$ squared is $4s^{2}$.

To raise a product to a power, apply the exponent to every factor inside the parentheses. Then work out any numerical powers, so $3^{2}$ becomes 9.