a)
[tex]4x=12 \ \ |:4\\\\\boxed{x=3}[/tex]
b)
[tex]4x-3=15\\\\4x=15+3\\\\4x=18 \ \ |:4\\\\\boxed{x=4,5}[/tex]
c)
[tex]x-6=5x-2\\\\x-5x=-2+6\\\\-4x=4 \ \ |:(-4)\\\\\boxed{x=-1}[/tex]
d)
[tex]4(x-2)=x+1\\\\4x-8=x+1\\\\4x-x=1+8\\\\3x=9 \ \ |:3\\\\\boxed{x=3}[/tex]
e)
[tex]\frac{2x-1}{2}=\frac{1-x}{4}\\\\4(2x-1)=2(1-x)\\\\8x-4=2-2x\\\\8x+2x=2+4\\\\10x=6 \ \ |:10\\\\\boxed{x=0,6}[/tex]
f)
[tex]4x-(3-x)=x+7\\\\4x-3+x=x+7\\\\4x+x-x=7+3\\\\4x=10 \ \ |:4\\\\\boxed{x=2,5}[/tex]
