27a -49b+2.4(6a-7b)-42a при a=10 и и b=-2 19,7x-32.3y-3.5(3x-8y)+10x при x=-20 и y=-5 ...

Question

27a -49b+2.4(6a-7b)-42a при a=10 и и b=-2

19,7x-32.3y-3.5(3x-8y)+10x при x=-20 и y=-5

Найдите значение выражений

Answer 1

27a-49b+2.4(6a-7b)-42a при а=10 и b=-2
27a-49b+14.4a-16.8b-42a
-0.6a-65.8b=-0.6*10-65.8*(-2)=6+131.6=137.6

Answer 2

27*10-49*(-2)+2.4(6*10-7*(-2))-42*10=270+98+177.6-420=125.6

Comments

19.7*(-20)-32.3*(-5)-3.5(3*(-20)-8*(-5))+10*(-20)=-394+161.5+70-200=-362.5