a-
(4y+5)²-3(y+1)(y-2)=16y²+40y+25-3(y²-2y+y-2)=16y²+40y+25-3y²+6y-3y+6=13y²43y+31
b-
(y+3)(y-3)+3y(2-5y)=y²-9+6y-15y²=-14y²+6y-9
c-
3(2y-10)²+(2y-3)(2y+3)=3(4y²-40y+100)+4y²-9=12y²-120y+300+4y²-9=16y²-120y+291
d-
(11y+1)²-(11y-1)²=121y²+22y+1-(121y²-22y+1)=121y²+22y+1-121y²+22y-1=44y
