Why do I keep getting this wrong?

• Apr 1st 2008, 02:06 AM
Coach
Why do I keep getting this wrong?
The problem

3x-(1+2x)=6 Please pretend the parenthesis are aboslute value bars

my solution

$-(1+2x)=-6+3x$divide both sides by -1

$(1+2x)=6-3x$

$1+2x=6-3x$ or $1+2x=-6-3x$

x= 1 or x=7, but only seven is valid in the original equation. Why?

• Apr 1st 2008, 02:15 AM
mr fantastic
Quote:

Originally Posted by Coach
The problem

3x-(1+2x)=6 Please pretend the parenthesis are aboslute value bars

my solution

$-(1+2x)=-6+3x$divide both sides by -1

$(1+2x)=6-3x$

$1+2x=6-3x$ or $1+2x=-6-3x$

x= 1 or x=7, but only seven is valid in the original equation. Why?