Question

плиз помогите дам 50 баллов​

Answer 1

$1)\;-\frac25\left(15a+\frac12b\right)+\frac15b=-\frac25\cdot15a-\frac25\cdot\frac12b+\frac15b=-2\cdot3a-\frac15b+\frac15b=-6a$

$2)\;4\frac25\left(\frac3{11}-a\right)-1\frac15=4\frac25\cdot\frac3{11}-4\frac25a-\frac65=\frac{22}5\cdot\frac3{11}-4\frac25a-\frac65=\frac65-4\frac25a-\frac65=\\\\=-4\frac25a$

$3)\;-\frac19\left(3b-9\right)+\frac13b=-\frac19\cdot3b+\frac19\cdot9+\frac13b=-\frac13b+1+\frac13b=1$

$4)\;-2\frac38\left(4c+\frac8{19}\right)+9\frac12c=-\frac{19}8\left(4c+\frac8{19}\right)+\frac{19}2c=-\frac{19}8\cdot4c+\frac{19}8\cdot\frac8{19}+\frac{19}2c=\\\\=-\frac{19}2c+1+\frac{19}2c=1$