If the root of the equation MX + 1 = 3x-3 about X is negative, then the value range of M?

If the root of the equation MX + 1 = 3x-3 about X is negative, then the value range of M?

mx+1-3x+3=0
mx-3x=-4
x(m-3)=-4
x=-(m-3)/4
x>0
So m < 3