Bonsoir,
Exercice 27 :
a. K = (a+1)²-(a-1)² = a²+2a+1-(a²-2a+1) = a²+2a+1-a²+2a-1 = 4a
b. 100001²-99999² = (100000+1)²-(100000-1)² = 4(100000) = 400000
Exercice 28 :
a. F = (2x+3)²-(4+3x)² = 4x²+12x+9-(16+24x+9x²) = 4x²+12x+9-16-24x-9x² = -5x²-12x-7
b. Pour x = -1, F = -5(-1)²-12(-1)-7 = -5(1)-12(-1)-7 = -5+12-7 = 0
Exercice 29 :
G = (3-5x)(3+5x)-(6x-2)² = 9-25x²-(36x²-24x+4) = 9-25x²-36x²+24x-4 = -61x²+24x+5
