substract 17 from both sides z+17 - 17 < -4 -17 17-17=0 z+0 < -21 z<-21 there will be no change in sign since you are not multiplying or dividng by a negtive number
which can be represented as (- infinity , 21)
note the parenthesis, less than and greater than will use a parenthesis less than and equal will use a bracket so will greater than and equal
