Je n'arrive pas à factoriser D , E et F , et développer E(y) . Merci

(2t+1)²+4t²-1
=(2t+1)(2t+1)+(2t+1)(2t-1)
=(2t+1)(2t+1+2t-1)
=4t(2t+1)

(5x-1)²+10x-2
=(5x-1)(5x-1)+2(5x-1)
=(5x-1)(5x+1+2)
=(5x-1)(5x+3)

x(x+2)-x-2
=x(x+2)-(x+2)1
=(x+2)(x-1)