\(3.\left(x-3\right)-4x+12=0\)
\(3x-9-4x+12=0\)
\(-9+12=-3x+4x\)
\(x=3\)
\(3.\left(x-3\right)-4x+12=0\)
\(3x-9-4x+12=0\)
\(3x-4x=9-12\)
\(-x=-3\)
\(x=3\)
C1:3(x-3)-4x+12=0
3(x-3)-4(x-3)=0
(x-3)(3-4)=0
x-3=0
x=0+3
x=3
C2: 3(x-3)-4x+12=0
3x-9-4x+12=0
3x-4x-9+12=0
-x+3=0
3-x=0
x=3-0
x=3
\(3.\left(x-3\right)-4x+12=0\)
\(3.\left(x-3\right)-4\left(x-3\right)=0\)
\(\left(x-3\right)\left(3-4\right)=0\)
\(\left(x-3\right).\left(-1\right)=0\)
\(-x+3=0\)
\(x=3\)