Toán D = ( x 2 − 7 ) ( x + 2 ) − ( 2 x − 1 ) ( x − 14 ) + x ( x 2 − 2 x − 22 ) + 35 19/07/2021 By Alaia D = ( x 2 − 7 ) ( x + 2 ) − ( 2 x − 1 ) ( x − 14 ) + x ( x 2 − 2 x − 22 ) + 35
`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` Trả lời
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}` Trả lời
`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`
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}`