Respuesta :
although the answer from Cindie17 is correct you can also do this:
3x-1=20, subtract 1 from both sides and get 3x=21, then divide both sides by 3 so 3x/3= x and 21/3=7
thus, x=7
3x-1=20, subtract 1 from both sides and get 3x=21, then divide both sides by 3 so 3x/3= x and 21/3=7
thus, x=7