Phrase one
Notice that there is a minus sign to the right of the 14; therefore, the first part of phrase one is
14 decreased by
On the other hand, 3z is a 3 multiplied by a number z.
Thus, the whole phrase is,
14 decreased by 3 times a number z.
Phrase two
Once again, 3z is 3 times a number z, and we need to subtract that term from 14; this is,
3 times a number z subtracted from 14.