Question

выполните действия 1) (7/15-1/6)+2/5 2) (3/8-1/9)+25/36 3)(8/9-5/6)+2/3 помогите решить пожалуйста.

Answer 1

$1)(ttdisplaystylefrac{7}{15}-frac{1}{6})+frac{2}{5}=(frac{7*2}{15*2}-frac{1*5}{6*5})+frac{2}{5}=(frac{14}{30}-frac{5}{30})+frac{2}{5}=frac{9}{30}+frac{2}{5}=frac{3}{10}+frac{2*2}{5*2}=frac{3}{10}+frac{4}{10}=frac{7}{10}$

$2)(ttdisplaystylefrac{3}{8}-frac{1}{9})+frac{25}{36}=(frac{3*9}{8*9}-frac{1*8}{9*8})+frac{25}{36}=frac{27-8}{72}+frac{25*2}{36*2}=frac{19}{72}+frac{50}{72}=frac{69}{72}=frac{23}{24}$

$3)(ttdisplaystylefrac{8}{9}-frac{5}{6})+frac{2}{3}=(frac{8*2}{9*2}-frac{5*3}{6*3})+frac{2}{3}=(frac{16-15}{18})+frac{2}{3}=frac{1}{18}+frac{2*6}{3*6}=frac{1+12}{18}=frac{13}{18}$