Solve the equation: |x+1|+|x-2|=3
|x+1|+|x-2|=3
x+1+x-2=3 or -(x+1)+x-2=3 or x+1-(x-2)=3 or -(x+1)-(x-2)=3
2x-1=3 or -x-1+x-2=3 or x+1-x+2=3 or -x-1-x+2=3
2x=2 or -3=3 or 3=3 or -2x+1=3
x=1 or rubbish or -2x=2
x=1 or x=-1
I have checked by substituting. (in my head)