solve the given equation for the variable:
6x - 3(x - 1) = 4(2x + 1)
$$6x - 3(x - 1) = 4(2x + 1)\\
6x-3x-3(-1) = 4*(2x)+4*1\\
6x-3x+3=8x+4\\
3x+3=8x+4 \quad | \quad -3x\\
3 = 8x-3x+4\\
3=5x+4 \quad | \quad -4\\
3-4=5x\\
-1=5x\\
5x=-1\quad | \quad :5\\
x=-\frac{1}{5}$$