Монгол Бодлогын Сан

Заавар: $$\begin{gather*} a^2-b^2=(a-b)(a+b)\\ ab+ac=a(b+c)\\ \sqrt{a^2b}=|a|\sqrt{b} \end{gather*}$$

Бодолт: $$\begin{align*} \text{Илэрх.}&=\sqrt{\dfrac{629^2-581^2}{480}}+\sqrt{20^2+15^2}\\ &=\sqrt{\dfrac{(629-581)(629+581)}{480}}+\sqrt{(5\cdot 4)^2+(5\cdot 3)^2}\\ &=\sqrt{\dfrac{48\cdot 1210}{480}}+\sqrt{5^2\cdot(4^2+3^2)}\\ &=\sqrt{121}+5\sqrt{25}\\ &=11+25=36 \end{align*}$$