Упр.846 ГДЗ Никольский Потапов 7 класс (Алгебра)

Задача

б) (1,75:2/3-1*3/4:1,25)*6;
в) (2-1/4*0,8):(0,16:1/2+0,01);
г) 3*3/4*12+(2,55+2,7)*(0,1-1/80).

Подробный ответ

а)

$$ (14{,}05-1\tfrac{1}{4}):0{,}04-13{,}8\cdot 13 $$
$$ (14{,}05-1{,}25):0{,}04-179{,}4 $$
$$ 12{,}8:0{,}04-179{,}4 $$
$$ 320-179{,}4=140{,}6 $$

б)

$$ (1{,}75:\tfrac{2}{3}-1\tfrac{3}{4}:1{,}25)\cdot 6 $$
$$ \left(\tfrac{7}{4}:\tfrac{2}{3}-\tfrac{7}{4}:\tfrac{5}{4}\right)\cdot 6 $$
$$ \left(\tfrac{21}{8}-\tfrac{7}{5}\right)\cdot 6 $$
$$ \left(\tfrac{105-56}{40}\right)\cdot 6 = \tfrac{49}{40}\cdot 6 = \tfrac{147}{20} = 7\tfrac{7}{20} $$

в)

$$ (2-\tfrac{1}{4}\cdot 0{,}8):(0{,}16:\tfrac{1}{2}+0{,}01) $$
$$ (2-0{,}25\cdot 0{,}8):(0{,}32+0{,}01) $$
$$ (2-0{,}2):0{,}33 $$
$$ 1{,}8:0{,}33=\tfrac{1{,}8}{0{,}33}=\tfrac{180}{33}=\tfrac{60}{11}=5\tfrac{5}{11} $$

г)

$$ 3\tfrac{3}{4}\cdot 12+(2{,}55+2{,}7)\cdot \left(0{,}1-\tfrac{1}{80}\right) $$
$$ \tfrac{15}{4}\cdot 12+5{,}25\cdot \left(\tfrac{1}{10}-\tfrac{1}{80}\right) $$
$$ 45+5{,}25\cdot \tfrac{7}{80} $$
$$ 45+\tfrac{525}{100}\cdot \tfrac{7}{80} = 45+\tfrac{147}{320} = 45\tfrac{147}{320} $$