remember, you can do anything to an equation as long as you do it to both sides
and when multiply or divide by a negative in inequalities, flip the direction of the sign
12x-39<9
add 39 to both sides
12x<48
divde bothh sides by 12
x<4
-4x+3<-6
minus 3 both sides
-4x<-9
times both sides by -1 and flip sign
4x>9
divide both sides by 4
x>9/4