... = (x-2)(x+2) - 7(x+2) = (x+2)(x-9) (1 đ)2)(x+1)(x+2)(x+3)(x+4) -3= (x+1)(x+4)(x+2)(x+3)-3= (x2+5x +4)(x2 + 5x+6)-3= [x2+5x +4][(x2 + 5x+4)+2]-3= (x2+5x +4)2 + 2(x2+5x +4)-3=(x2+5x ... + − ( ) ( ) ( ) ( ) ( )1 1x y x y x xy y xyx y x y+ − + − + −=+ + − ( ) ( ) ( ) ( ) ( ) ( )1 1 1 11 1x x y x y x xx y+ − + + + −=+ − ( )1x y y y xy− + −=− ( ) ( ) ( ) ( )1 ... 3, c = - 11, a = - 10 Ta có (x - 10) (x - 4) - 7 = (x - 3)(x - 11)Trường hợp thứ hai cho b = 3, c = - 5, a = 2Ta có (x + 2)(x - 4) - 7 = (x + 3)(x - 5) Bài 3. Đặt : ( ) ( )11u x xv y y=...