Пошаговое объяснение:
2) 5x-(x-2); x=-5
5*(-5)-(-5-2)=-25+7=-18
4)x-2(x+5); x=-7
-7-2*(-7+5)=-7-2*(-2)=-7+4=-3
6) x-2*(x+7); x=-12
-12-2*(-12+7)=-12-2*(-5)=-12+10=2
8) 81/88*(6-28/15*40/21)=81/88*(6-28/3*8/21)=81/88*(6-226/63)=
=81/88*((378-226)/63)=81/88*152/63=9/11*19/7=108/77
10)81/16-9/8*(88/84)=81/-9/8*88/84=81/16-33/28=(1944-528)/448=1416/448=177/56
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готовы
