... 5((x2 - 2xy + y2) - 4z2) = ((x-y )2 (2z )2) = 5(x - y 2z)(x - y + 2z) Biểu điể m 0 ,25 0 ,25 0 ,25 0 ,25 0,5 0 ,25 0,5 0 ,25 K : x a) 0 ,25 P = 0 ,25 2x x 2x x + + x + ( x 2) ( x + 2) x2 2x(x - 2) ... 3, 42 = 1, 62 + 2. 1,6.3,4 + 3, 42 = (1,6 + 3,4 )2 = 52 = 25 a, x2 + 2xy + y2 -16 = (x2 + 2xy + y2) 16= (x + y )2 - 42 = (x + y 4)(x + y + 4) b, 5x2 -10 xy + 5y2 - 20 z2 = 5(x2 - 2xy + y2 - 4z2) = ... a, x2 + 2xy + y2 -16 = (x2 + 2xy + y2) 16= (x + y )2 - 42 = (x + y 4)(x + y + 4) 2 b, 5x -10 xy + 5y - 20 z2 = 5(x2 - 2xy + y2 - 4z2) = 5((x2 - 2xy + y2) - 4z2) = ((x-y )2 (2z )2) = 5(x - y 2z)(x...