ANSWER:
1. [tex]2x-4x-2=0\\-2x-2=0\\-2x-2+2=0+2\\-2x=2\\\frac{-2x}{-2}=\frac{2}{-2}\\x=-1[/tex]
2. [tex]x-16=0\\x-16+16=0+16\\x=16[/tex]
3. [tex]3x\left(-7\right)x=0\\-21x^2=0\\\frac{-21x^2}{-21}=\frac{0}{-21}\\x^2=0\\x=0[/tex]
4. [tex]\left(x+1\right)\left(x+6\right)=0\\x+1=0\quad \mathrm{or}\quad \:x+6=0\\x=-1,\:x=-6\\\\x+1-1=0-1\\x=-1\\x+6=0\\x+6-6=0-6\\x=-6\\\\x=-1,\:x=-6[/tex]
