Bonjour,
Ex. 41 :
A = 2 × n + 2 × 7 = 2 × (n + 7)
B = 2 × n + 5 × n = (2 + 5) × n
C = 10 × n + 10 = 10 × n + 10 × 1 = 10 × (n + 1)
D = 9 × n - 15 = 3 × 3 × n - 3 × 5 = 3 × (3 × n - 5)
E = n × 6 - 8 × n = n × 2 × 3 - 2 × 4 × n = 2n × (3 - 4)
F = n × n - 5 × n = n × (n - 5)
G = 24n - 24 = 24 × n - 24 × 1 = 24 × (n - 1)
H = 12n × n + 2 × n = 6 × 2 × n × n + 2 × n × 1 = 2n × (6n + 1)
Ex. 43 :
4x + 12 = 4(x+3)
6x - 15 = 3(2x-5)
21x - 7x = 7x(3-1) = 7x(2)
4 - 10x = 2(2-5x)
9x² + 6 = 3(3x²+3)
x² - 4x = x(x-4)
2x + 2 = 2(x+1)
x² + x = x(x+1)
4x² + 3x² = x²(4+3) = x²(7)
