Ответ:
Используем формулу разности квадратов: \(x^2-y^2=(x-y)(x+y)\).
- \(\sqrt{(41-40)(41+40)}=\sqrt{81}=9\).
- \(\sqrt{(145-144)(145+144)}=\sqrt{289}=17\).
- \(\sqrt{(8.5-7.5)(8.5+7.5)}=\sqrt{16}=4\).
- \(\sqrt{(21.8-18.2)(21.8+18.2)}=\sqrt{144}=12\).
- \(\sqrt{\dfrac{(155-134)(155+134)}{84}}=\sqrt{\dfrac{21\cdot289}{84}}=\sqrt{\dfrac{289}{4}}=8.5\).
- \(\sqrt{\dfrac{(139-86)(139+86)}{(98.5-45.5)(98.5+45.5)}}=\sqrt{\dfrac{53\cdot225}{53\cdot144}}=\sqrt{\dfrac{25}{16}}=\dfrac54\).
