Упр.525 ГДЗ Муравин 6 класс (Математика)

Задача

1) (-0,45•0,71) :(-0,9);
2)-190:(1,9•25);
3) (-9/28)•(-15 5/9) :5;
4) (4/5-5/6+2/15) :(-1/30);
5) (0,49+0,35) :(-0,7);
6)-0,2:0,5-0,3:0,5;
7)-2 3/5 :0,25:(-0,4);
8)-3 15/17 :(-8,9•3 15/17).

Подробный ответ

1) $$(-0,45\cdot 0,71):(-0,9)=(-0,45:(-0,9))\cdot 0,71=0,5\cdot 0,71=0,355.$$

2) $$-190:(1,9\cdot 25)=(-190:1,9):25=-100:25=-4.$$

3) $$\left(-\frac{9}{28}\right)\cdot\left(-15\frac{5}{9}\right):5=\left(-15\frac{5}{9}:5\right)\cdot\left(-\frac{9}{28}\right)$$
$$=\left(-\frac{140}{9}\cdot\frac{1}{5}\right)\cdot\left(-\frac{9}{28}\right)=-\frac{28}{9}\cdot\left(-\frac{9}{28}\right)=1.$$

4) $$\left(\frac{4}{5}-\frac{5}{6}+\frac{2}{15}\right):\left(-\frac{1}{30}\right)=\frac{4}{5}:\left(-\frac{1}{30}\right)-\frac{5}{6}:\left(-\frac{1}{30}\right)+\frac{2}{15}:\left(-\frac{1}{30}\right)$$
$$=-\frac{4}{5}\cdot 30+\frac{5}{6}\cdot 30-\frac{2}{15}\cdot 30=-24+25-4=-3.$$

5) $$\left(0,49+0,35\right):(-0,7)=0,49:(-0,7)+0,35:(-0,7)=-0,7-0,5=-1,2.$$

6) $$-0,2:0,5-0,3:0,5=(-0,2-0,3):0,5=-0,5:0,5=-1.$$

7) $$-2\frac{3}{5}:0,25:(-0,4)=-2\frac{3}{5}:\bigl(0,25\cdot(-0,4)\bigr)$$
$$=-\frac{13}{5}:(-0,1)=\frac{13}{5}:\frac{1}{10}=\frac{13}{5}\cdot\frac{10}{1}=26.$$

8) $$-3\frac{15}{17}:(-8,9\cdot 3\frac{15}{17})=\left(-3\frac{15}{17}:3\frac{15}{17}\right):(-8,9)$$
$$=-1:(-8,9)=\frac{1}{8,9}=\frac{10}{89}.$$