Svp un petit DM de Maths 47,48 SVP

bonjour,

A) x^4+4x²+4

B) 4x²+4x+1+4x²+4x+1-8x² = 8x²+2

C) 2(9t²-30t+25)-2(1-8t+16t²) =
     18t²-60t+50-16t²+8t-1 =
     2t²-52t+49

D) 1+8y+16y²-(4y²+12y+9)-(2y+3+8y²+12y) =
     1+8y+16y²-4y²-12y-9-2y-3-8y²-12y =
     4y²-18y-11