a) (2x + 3) ^ 2 -4(x-2).(x+2) b) (x + 6)/(x ^ 2 – 4) – 2/(x(x + 2)) C) (4x ^ 2 – 7x + 12) / (x + 1)

1 bình luận về “a) (2x + 3) ^ 2 -4(x-2).(x+2) b) (x + 6)/(x ^ 2 – 4) – 2/(x(x + 2)) C) (4x ^ 2 – 7x + 12) / (x + 1)”

1. Giải:

   a) (2x+3)²-4(x-2)(x+2)

   =4x²+12x+9-4(x²-4)

   =4x²+12x+9-4x²+16

   =12x+25

   b) (x+6)/x²-4 -2/x(x+2)

   =x(x+6)/x(x²-4)-2(x-2)/x(x²-4)

   =x²+6x-2x+4/x(x²-4)

   =x²-4x+4/x(x²-4)

   =(x-2)²/x(x-2)(x+2)

   =x-2/x(x+2)

   câu c khó quá,sry nha

   Trả lời