... tênh. Q = 2 2 2 2 2 1 2 :4xxxxxxxx−=−+−− HS1:a) = 2 2 )2( )1(++xx HS2:b) = 2 2 )2( )3(++xxHS:a) )7 (2 5) 42( :7105 22 +=−+−xxxxc) )1(35533:5105 2 2−=−++−+xxxxxxxxHoảt ... hồûc x = -2, 5.VD3: Gii phỉång trçnh:2x3 = x 2 + 2x -1VD2: Gii phỉång trçnh:(x +1) (x +4) = (2- x) ( 2 +x).⇔x 2 + x + 4x + 4 -2 2 + x 2 = 0⇔ x( 2x +5) = 0⇔ x = 0 hồûc x = -2, 5.VD3: ... x3 - 3x 2 -4x + 12. b)2x 2 - 2y 2 -6x -6y.c) x3 +3x 2 - 3x -1.d) x4 - 5x 2 + 4.Bi 7: Tçm x biãút:a)3x3 - 3x = 0.b) x3 + 36 = 12x.a) = (x -3) (x -2) (x +2) b) = 2 (x +y) (x...