Question

помогите, чем сможете ​

Answer 1

$1) \ 12,1a+\dfrac{1}{3}(5-9a)=12,1a+\dfrac{5}{3}-3a=9,1a+1\dfrac{2}{3}\\\\\\2) \ 12,9b-(5-9a)+3(a-4,3b)=12,9b-5+9a+3a-12,9b=12a-5\\\\12a-5=12\cdot1,1-5=13,2-5=8,2\\\\\\3)6a-9(a-1)+3(a-3)=6a-9a+9+3a-9=9a-9a=0$