Question

найдите значение выражения (7/20 - 8/15)в квадрате + 4/5 *(7/20 - 9/16)

Answer 1

$(frac{7}{20}- frac{8}{15})^2+ frac{4}{5}*( frac{7}{20}- frac{9}{16} )= frac{2413}{3600} \ \ 1) frac{7}{20}- frac{9}{16}= frac{28-45}{80}=- frac{17}{80} \ \2) - frac{17}{80}* frac{4}{5}=- frac{17}{100} \ \ 3) ( frac{7}{20}- frac{8}{15})^2= (frac{7}{20})^2-2* frac{7}{20}* frac{8}{15}+( frac{8}{15})^2= frac{49}{400}- frac{112}{300}+ frac{64}{225}= \ \ frac{49}{16}- frac{112}{12}+ frac{64}{9}= frac{147-448}{48}+ frac{64}{9}=$$- frac{301}{48}+ frac{64}{9} = frac{-2709+3072}{432}= frac{363}{432} \ \ 4) frac{-17}{100}+ frac{363}{432}= frac{-7344+36300}{43200}= frac{28956}{43200}= frac{2413}{3600}$