Réponse :
58)
a) (x+5)² - 21 + 2x = x² + 10x + 25 - 21 + 2x = x² + 12x + 4
b) 4(2x-3)² = 4(4x² -12x + 9) = 16x² - 48x + 36
c) 3(t-2)² + 1 = 3(t² - 4t + 4) + 1 = 3t² - 12t + 13
d) -2(x+4)² + 4x + 7 = -2(x² + 8x + 16) + 4x + 7 = -2x² - 12x - 25
59)
A = (2t - 4)² + 12 = (2 * (t-2))² + 12 = 2² * (t-2)² + 12 = 4 * (t-2)² + 12 = B
B = 4 (t-2)² + 12 = 4 (t-2)² - 4 + 16 = 4 * ( (t-2)² - 1 ) + 16
or a² - b² = (a+b) * (a-b)
B = 4 * ( (t-2 + 1) * (t-2 - 1) ) + 16 = 4 * (t - 1) * (t - 3) + 16 = C
Explications étape par étape
