... 4x -10 x+7 x x - + - =0 4x -10 x+7 4x-8 x+7 4x-16 x+7 4x-16 x+7 + =0 2(4x-8 x+7) 2(4x -10 x+7) 1 ổ + (4x-16 x+7).ỗ ữ=0 2(4x-8 x+7) 2(4x -10 x+7)ứ ố (1) Ta thy: 4x-8 x+7 = 4( x - 1)2 + > v 4x -10 ... (a,b) Ta cú 121 = x(c,d) Ê x(c - 1, d) + Ê x(c - 2, d) + 10 Ê x(a, d) + 5( c - a) Ê x(a, b) + 5( c - a) + 5(d - b) Ê + 5(11 -1) + 5(11 - 1) = 101 ( vụ lý) ị iu gi s l sai (pcm) Cõu 3: $ $ Kộo di ... Ta thy: 4x-8 x+7 = 4( x - 1)2 + > v 4x -10 x+7 = (2 x + )2 + > 1 ổ + ịỗ ữ > (2) ố2(4x-8 x+7) 2(4x -10 x+7)ứ ộx=49 ( tha iu T (1) v (2) suy 4x -16 x+7 = (2 x - 7)(2 x - 1) = ị ờx=1 kin) b) Vỡ x =...