D = ( x 2 − 7 ) ( x + 2 ) − ( 2 x − 1 ) ( x − 14 ) + x ( x 2 − 2 x − 22 ) + 35

0 bình luận về “D = ( x 2 − 7 ) ( x + 2 ) − ( 2 x − 1 ) ( x − 14 ) + x ( x 2 − 2 x − 22 ) + 35”

1. `D = (x^2 – 7)(x+2)-(2x-1)(x-14)+x(x^2-2x-22)+35`

   `= x^3 + 2x^2 – 7x – 14 – (2x-1)(x-14)+x(x^2-2x-22)+35`

   `= x^3 + 2x^2 – 7x – 14 – 2x^2 + 29x – 14 + x(x^2-2x-22)+35`

   `= x^3 + 2x^2 – 7x – 14 – 2x^2 + 29x – 14 + x^3 – 2x^2 – 22x + 35`

   `= 2x^3 – 2x^2 – 14 – 14 + 35`

   `= 2x^3 – 2x^2 + 7`

   Vậy `D = 2x^3 – 2x^2 + 7`

   Bình luận

2. Đáp án:

   `D=2x³-2x²+7`

   Giải thích các bước giải:

   `D=(x²-7)(x+2)-(2x-1)(x-14)+x(x²-2x-22)+35`

   `D=x³+2x²-7x-14-(2x²-28x-x+14)+x³-2x²-22x+35`

   `D=x³+2x²-7x-14-2x²+28x+x-14+x³-2x²-22x+35`

   `D=(x³+x³)+(2x²-2x²-2x²)+(-7x+28x+x-22x)+(-14-14+35)`

   `D=2x³-2x²+7`

   `text{Vậy D=2x³-2x²+7}`

   Bình luận