Bonsoir,
1) a) (x-2)² = (x-2)(x-2) = x²+(-2x)+(-2x)+(-2)² = x²-4x+4
b) 98² = (100-2)(100-2) = 100²-4(100)+4 = 10 000 - 400 + 4 = 9 604
2) a) (x-2)(x+2) = x²+2x+(-2x)+(-4) = x²-4
b) 98 × 102 = (100-2)(100+2) = 100²-4 = 10 000 - 4 = 9 996
