Final: Area, Expanded

The area of the first bed is $\left(x+5\right)\left(x+2\right)$. Expanding it gives four products: $x^{2}$, $2x$, $5x$ and $10$. Collecting the two middle terms gives $x^{2}+7x+10$.

The factored form shows the two sides. The expanded form shows how the area changes as $x$ changes, term by term. Both forms are equal for every value of $x$.