5(x+4)+2x=6-4(2x+3)+7

The answer my calculator gives is -19/15.
How did they get that?

3 answers

5x+20+2x=6-8x-12+7
add 8x to both sides
15x+20=1
15x=-19
divide by 15
after i add 8x though
i'm left with
13x+20+10x=6-12+7
Does anyone know?