Помогите пожалуйста

№1

а)

$1,3-7\frac{1}{6} +3,89-1\frac{3}{10}-1\frac{5}{6}+2,11= 7,3-9-1,3= 6-9=-3$

б)

$3,5*(-\frac{2}{7})*(-0,05)*2\frac{1}{6}*(-20)= 3,5*(-\frac{2}{7})*\frac{13}{6} * 1 = -\frac{10}{10}*\frac{13}{6} = 2\frac{1}{6} \\$

№ 2

а)

$\frac{4}{11} * (-\frac{8}{9})-\frac{8}{9} *\frac{7}{11} =\frac{8}{9}(-\frac{4}{11}-\frac{7}{11})=\frac{8}{9} * (-1)=-\frac{8}{9}$

б)

$(-3\frac{2}{7}+2,4)*7=-\frac{23}{7}*7+2,4*7=-23+16,8=-6,2$

№3

а)

$-7,2(3x+6,3)=0\\-21,6x-45,36=0\\-21,6x=45.36\\x=2,1$

б)

$(x-\frac{2}{3} )*(x+1.5)=0\\(x-\frac{2}{3})=0\\x_{1} = \frac{2}{3} \\x+1,5=0\\x_{2} = -1,5$