Вычислить значения a за формулой a=86 - 5b если b=17;b=9

1. 1) I urgently need to go to the store and buy milk.2) Mike told me homework .3) Today were given tickets for the film .4) According to Russian asked two exercises .5) In mathematics I had to do the last number .6) Holidays come to an end next month.7) I went to the Comedy Theatre.

b=17       a=86-5b=86-5*17=86-85=1b=9         a=86-5b=86-5*9=86-45=41