Question

2 вычислите 
(1. 1/3 - 2. 5/6):(0.75-1. 1/6)
(-1.25+1. 7/8):(-1. 1/12-0/5)
3 решить уровнения
а)2*(0.4х-1.2)=х+1.4
б)х-1. 2/7=4x+2. 5/14
в)3*(0.4x+1.4)=x-0.8
г) 3x+1. 2/9+x-3. 10/27
4 решить пример
4/7*(1.4*-1. 7/8 - 3.5)+1.2*(3-2*-1. 7/8)

Answer 1

$(1 frac{1}{3} - 2 frac{5}{6}):(0.75-1 frac{1}{6})=( frac{4}{3} - frac{17}{6}):( frac{3}{4}- frac{7}{6})= \ =( frac{8}{6} - frac{17}{6}):( frac{9}{12}- frac{14}{12})=- frac{9}{6} :(- frac{5}{12})=frac{9}{6}cdot frac{12}{5}= frac{108}{30} =3.6 \ (-1.25+1 frac{7}{8}):(-1 frac{1}{12}- frac{0}{5})=(- frac{5}{4}+frac{15}{8}):(- frac{13}{12})=(- frac{10}{8}+frac{15}{8}):(- frac{13}{12})= \ = frac{5}{8}cdot(- frac{12}{13})=- frac{60}{104}=- frac{15}{26}$
$2(0.4x-1.2)=x+1.4 \ 0.8x-2.4=x+1.4 -0.2x=3.8 \ x=-19$
$x-1 frac{2}{7}=4x+2 frac{5}{14} \ x- frac{9}{7}=4x+ frac{33}{14} \ 14x-18=56x+33 \ -42x=51 \ x=- frac{51}{42} =- frac{17}{14}$
$3(0.4x+1.4)=x-0.8 \ 1.2x+4.2=x-0.8 \ 0.2x=-5 \ x=-25$
$3x+1 frac{2}{9}+x-3 frac{10}{27}=0 \ 3x+ frac{11}{9}+x-frac{91}{27}=0 \ 81x+ 33+27x-91=0 \ 108x=58 \ x= frac{58}{108} =frac{29}{54}$
$frac{4}{7}(1.4cdot(-1 frac{7}{8})- 3.5)+1.2(3-2cdot(-1 frac{7}{8}))= \ = frac{4}{7}(-2.625- 3.5)+1.2(3+3.75)= frac{4}{7}cdot(-6.125)+1.2cdot6.75= \ =-3.5+8.1=4.6$