a)
[tex]3(x-3)=3x-9\\5(y+z)=5y+5z\\4(3x-y)=12x-4y\\-2(7-4n)=-14+8n[/tex]
b)
[tex]\frac{1}{2} (4z+2)=2z+1\\-\frac{1}{3} (6b-3)=-2b+1\\0,2(x-5y)=0,2x-y\\3(\frac{1}{3} a+1)=a+3[/tex]