bjr
comme (a+b) (c+d) = ac + ad + bc+ bd
on aura
A = x * x + x * 5 + 2 * x + 2 * 5
= x² + 5x + 2x + 10
= x² + 7x + 10
B = 3x * 5x + 3x * (-2) - 7 * 5x - 7 * (-2)
= 15x² - 6x - 35x + 14
= 15x² - 41x + 14
C = x * 4 + x * (-x) + 3 * 4 + 3 * (-x)
vous terminez :)
D = (a+b) (a-b) = a² - b²
= (4x)² - 5² = 16x² - 25
