\(\text{a) -3000 : 2 + 5(2x-1) = 125}\\ -1500+5\left(2x-1\right)=125\\ 5\left(2x-1\right)=125-\left(-1500\right)\\ 5\left(2x-1\right)=1625\\ 2x-1=1625:5\\ 2x-1=325\\ 2x=325+1\\ 2x=326\\ x=326:2\\ x=163\)
\(\text{b) 6x -12 = -18}\\ 6x=-16+12\\ 6x=-6\\ x=-1\)
\(\text{c) 17 + 3(x-1) = 5}\\ 3\left(x-1\right)=5-17\\ 3\left(x-1\right)=-12\\ x-1=-12:3\\ x-1=-4\\ x=-3\)
\(\text{d) (x-5) (3x-6) = 0}\\ \left[{}\begin{matrix}x-5=0\\3x-6=0\end{matrix}\right.\\ \left[{}\begin{matrix}x=5\\x=2\end{matrix}\right.\)