70-(8х-3)(8х+3) (5а+3)в кв +(5а-3)(5а+3)

70-(8х-3)(8х+3)=70-(64х²-9)=70-64х²+9=79-64х² (5а+3)²+(5а-3)(5а+3)=25а²+30а+9+25а²-9=50а²-30а=10а(5а-3)