Question

СРОЧНО ВАРИАНТ ПЕРВЫЙ СРОЧНОО

Answer 1

Ответ:

1)

  $2.8(0,5a+4)-2,5(2a-6)=\\1.4a+11.2-5a+15\\-3.6+26.2$

2)

   $2(7-5b)+15b-3(2b+5)=\\14-10b+15b-6b-15\\14-b-15\\-1-b$

3)

  $(-\frac{5}{9}+1\frac{20}{21}):1\frac{8}{49}-1\frac{7}{9}:(-6)=\\(-\frac{5}{9}+\frac{21+20}{21}):\frac{49+8}{49}-\frac{9+7}{9}:(-6)\\(-\frac{35}{63}+\frac{123}{63}):\frac{57}{49}-\frac{16}{9}:(-6)\\\frac{88}{63}:\frac{57}{49}+\frac{8}{27}\\\frac{616}{513}+\frac{8}{27}\\\\=\frac{256}{171}$

4)

   $1.6(\frac{1}{8}*0.25+2.5*5.7)-(4.5*5.7-1\frac{1}{2}*0.25)(-2)-(-12*0.25+14*5.7)=\\1.6(\frac{1}{8}*\frac{1}{4}+14.25)-(25.65-\frac{1*2+1}{2}*0.25)(-2)-(-3+79.8)\\1.6(\frac{1*1}{8*4}+14.25)-(25.65-\frac{3}{2}*\frac{1}{4})(-2)-(76.8)\\1.6(\frac{1}{32}+14.25)-(25.65-\frac{3*1}{2*4})(-2)-76.8\\1.6(\frac{1}{32}+\frac{57}{4})-(\frac{513}{20}-\frac{3}{8})(-2)-76,8\\1.6(\frac{1}{32}+\frac{456}{32})-(\frac{1026}{40}-\frac{15}{40})(-2)-76.8\\1.6(\frac{1+456}{32})-(\frac{1026-15}{40})(-2)-76.8$

   $1.6*(\frac{457}{32})-\frac{1011}{40}(-2)-76.8\\\frac{8}{5}*\frac{457}{32}-\frac{1011(-2)}{40}-76.8\\\frac{8*457}{5*32}-\frac{-2022}{40}-76.8\\\frac{3656}{160}-(-\frac{1011}{20})-76.8\\\frac{457}{20}+\frac{1011}{20}-76.8\\\frac{457+1011}{20}-76.8\\\frac{1468}{20}-76.8\\\frac{367}{5}-76.8\\\frac{367}{5}-\frac{384}{5}\\\frac{367-384}{5}\\-\frac{17}{5}$