Question

Найдите значение выражения ) 7/9*(1.8а-2.7)+0.6(2-3а), если а=-1 7/8

Answer 1

7/9*18/10a-7/9*27/10+0,6*2-0,6*3a=1,4a-2,1+1,2-1,8a=-0,4a-0,9
a=-1 7/8    4/10*(-15/8)-0,9=-0,75-0,9=-1,65

Answer 2

$\frac{7}{9} *(1.8a-2.7)+0.6(2-3a) \\ \\ 1)\frac{7}{9} * \frac{18}{10} a- \frac{7}{9} * \frac{27}{10} = \frac{7*2}{10} a- \frac{7*3}{10} = \frac{14}{10} a- \frac{21}{10} =1.4a-2.1 \\ \\ 2) 0.6*(2-3a)=1.2-1.8a \\ \\ 3) 1.4a-2.1+1.2-1.8a=1.4a-1.8a+1.2-2.1= \\ =-0.4a-0.9 \\ a=-1 \frac{7}{8} =-1.875 \\ \\ -0.4*(-1.875)-0.9=0.75-0.9=-0.15$