(4x-1)(5x-2)-16x²+1=0 => (4x-1)(5x-2) - (4x-1)(4x+1) = 0 => (4x-1)(x-3) = 0
c'est toujours la règle du produit nul
4x - 1 = 0 => x = 1/4 ou x-3 = 0 => x = 3
9/4x²+3x+1=0 => (3/2x + 1)² = 0 => 3/2x = -1 => x = -2/3
6x+4-(2x-5)(9x+6) = 0 => 2(3x+2) -3(3x+2)(2x-5) = 0 => (3x+2)(2 - 6x+15) = 0
=> (3x+2)(17-6x) = 0 => x = -2/3 ou x = 17/6
x² - 10x + 25 = 0 => (x-5)² = 0 => x = 5