(2y-1)²-(2y+3)+3y²+(2y+1)²=4y²-4y(-...

(2y-1)²-(2y+3)+3y²+(2y+1)=4y²+1-2y-3+3y²+2y+1=7y²-1

(2y-1)²-(2y+3)+3y²+(2y+1)²=4y²-4y+1-2y-3+3y²+4y²+4y+1 =11y²-2y-1