Question 82208
1. {{{(6x-2)+(2x+4)=6x+2x-2+4=8x+2}}}

2. {{{(f^2+4f-1) + (2f^2- 3f +2)=f^2+2f^2+4f-3f-1+2=3f^2+f+1}}}

3.{{{(5+2a+3a^2) - ( a^2+a-6)}}} this one has a negative in front of second parenthesis so you have to be very careful, and make sure when you open parenthesis that you change the sign of all the terms in those parenthesis (because that negative is like multiplying all those terms by (-1) so
{{{= 5+2a+3a^2-a^2-a+6=2a^2+a+11}}}

4. solve the equation {{{4(x-2)=0}}} multiply through
{{{4x-8=0}}}
{{{4x=8}}} divide both sides by 4, you get
{{{x=2}}}
 

good luck