655 Вправа 655Алгебра 8 клас Бевз 2025 · § 13 · стор. 128

655. Обчисли значення виразу.

а) ${\displaystyle \frac{2}{7}\sqrt{784}-\frac{3}{4}\sqrt{676}=}$${\displaystyle \frac{2}{7}\cdot 28-\frac{3}{4}\cdot 26}$=

=${\displaystyle \frac{2\cdot 4\cdot \cancel{7}}{\cancel{7}}-\frac{3\cdot \cancel{2}\cdot 13}{\cancel{2}\cdot 2}=}$${\displaystyle 8-\frac{39}{2}=}$${\displaystyle 8-19,5=}$${\displaystyle -11,5}$;

б) ${\displaystyle \frac{3}{5}\sqrt{3025}-29\sqrt{0,01}=}$${\displaystyle \frac{3}{5}\cdot 55-29\cdot 0,1}$=

=${\displaystyle 33-2,9=}$${\displaystyle 30,1}$;

в) ${\displaystyle -\frac{1}{2}\sqrt{1156}+17\sqrt{0,04}=}$${\displaystyle -\frac{1}{2}\cdot 34+17\cdot 0,2}$=

=${\displaystyle -17+3,4=}$${\displaystyle -13,6}$;

г) ${\displaystyle -\sqrt{7056}-380\sqrt{0,25}=}$${\displaystyle -84-380\cdot 0,5}$=

=${\displaystyle -84-190=}$${\displaystyle -274}$.