-10x+9x+14-1=4
then you add similar elements which gives you -x+14-1=4
next you subtract the numbers 14-1=13
then subtract 13 from each side -x+13-13=4-13
then you simplify -x = -9
divide both sides my negative 1 -x/-1 = -9/-1
and then you get the answer: x=9
