Question

Помогите кто-нибудь!!!! Сроооочно!!!! Даю 45 баллов!!!
-2x+(1/3x+7)=-21
12+3(x-1)=0

Answer 1

$1)-2x+(\frac{1}{3}x+7)=-21\\\\-2x+\frac{1}{3}x+7=-21\\\\-1\frac{2}{3}x=-28\\\\\boxed{x=16,8}\\\\\\2)12+3(x-1)=0\\\\12+3x-3=0\\\\3x=-9\\\\\boxed{x=-3}$

Answer 2

$-2x+(\frac{1}{3} x+7)=-21\\\\-2x+\frac{1}{3}x+7=-21\\\\-\frac{6}{3} x+\frac{1}{3} x=-21-7 \\\\-\frac{5}{3}x=-28\\\\x=-28:(-\frac{5}{3} )\\\\x=28*\frac{3}{5} \\\\x=\frac{84}{5} =16\frac{4}{5}$

________________

$12+3(x-1)=0\\12+3x-3=0\\3x+9=0\\3x=-9\\x=-3$