Question 789983
{{{b-(-3b-3)=4b+3}}}...we can prove that left side is equal to right side

{{{b+3b+3=4b+3}}}

{{{4b+3=4b+3}}}...proof



{{{2-(-9)=11}}}
{{{2+9=11}}}
{{{11=11}}}
 as you said, the other side of equation is ok(11 of course).Is it because the 2 negative signs(one inside parenthesis)and the positive 2 in front makes the 9 positive--this is {{{correct}}}

now, your question: any number inside absolute value sign will become positive-if the number is negative 

that is {{{true}}}; recall definition of absolute value

the absolute value of a number is the {{{distance}}} the number is {{{from}}} {{{zero}}} (on a number line}}}

example: 
{{{abs(-3)=3}}}, on number line {{{-3}}} is {{{3}}} units to the left from zero
{{{abs(3)=3}}}, on number line {{{3}}} is {{{3}}} units to the right from zero