Question

): выражение: это знак /,означает черту дроби -2/5(15а+1/2b)+1/5b= 4целых2/5(3/11-а)-1целая1/5= -1/9(3b-9)+1/3b= -2целых3/8(4с+8/19)+9целых1/2с=

Answer 1

$1)- \frac{2}{5} (15a+ \frac{1}{2}b )+\frac{1}{5}b=-\frac{2}{5}*15a-\frac{2}{5}*\frac{1}{2}b+\frac{1}{5}b=-6a-\frac{1}{5}b+\frac{1}{5}b=-6a$

$2)4\frac{2}{5}(\frac{3}{11}-a)-1 \frac{1}{5}=4\frac{2}{5}*\frac{3}{11}-4\frac{2}{5}*a-1 \frac{1}{5}=4\frac{6}{55}-1\frac{11}{55}-4\frac{2}{5}a=2-4.4a$

$3)- \frac{1}{9} (3b-9)+ \frac{1}{3}b= - \frac{3}{9} b+ \frac{9}{9} + \frac{1}{3}b=- \frac{1}{3} b+1+ \frac{1}{3}b=1$

$4)- 2\frac{3}{8} (4c+ \frac{8}{19} )+9 \frac{1}{2}c=-2 \frac{3}{2}c -2 \frac{3}{19} +9 \frac{1}{2}c=6c-2 \frac{3}{19} =2(3c-\frac{3}{19})$