a) (1phần2x – 3) mũ 3 =? b) (2x+1)mũ3 =? c) (2x + 1) mũ 3 =? d) (3x-1phần2)mũ 2 =? 20/07/2021 Bởi Athena a) (1phần2x – 3) mũ 3 =? b) (2x+1)mũ3 =? c) (2x + 1) mũ 3 =? d) (3x-1phần2)mũ 2 =?
a. `(1/2x-3)^3` `=(1/2x)^3+3*(1/2x)^2*3+3*1/2x*3^2+3^3` `=1/8x^3+9/4x^2+27/2x+27` b. `(2x+1)^3` `=(2x)^3+3*(2x)^2*1+3*2x*1^2+1^3` `=8x^3+12x^2+6x+1` c. `(2x+1)^3` `=(2x)^3+3*(2x)^2*1+3*2x*1^2+1^3` `=8x^3+12x^2+6x+1` d. `(3x-1/2)^2` `=(3x)^2-2*3x*1/2+(1/2)^2` `=9x^2-3x+1/4` Bình luận
Đáp án: Giải thích các bước giải: $\left (\dfrac{1}{2}x-3 \right )^3$ $=\dfrac{1}{8}x^3-\dfrac{9}{4}x^2+\dfrac{27}{2}x -27$ $(2x+1)^3$ $=8x^3+12x^2+6x+1$ $(2x+1)^3$ $=8x^3+12x^2+6x+1$ $\left (3x-\dfrac{1}{2} \right )^2$ $=9x^2-3x+\dfrac{1}{4}$ Bình luận
a.
`(1/2x-3)^3`
`=(1/2x)^3+3*(1/2x)^2*3+3*1/2x*3^2+3^3`
`=1/8x^3+9/4x^2+27/2x+27`
b.
`(2x+1)^3`
`=(2x)^3+3*(2x)^2*1+3*2x*1^2+1^3`
`=8x^3+12x^2+6x+1`
c.
`(2x+1)^3`
`=(2x)^3+3*(2x)^2*1+3*2x*1^2+1^3`
`=8x^3+12x^2+6x+1`
d.
`(3x-1/2)^2`
`=(3x)^2-2*3x*1/2+(1/2)^2`
`=9x^2-3x+1/4`
Đáp án:
Giải thích các bước giải:
$\left (\dfrac{1}{2}x-3 \right )^3$
$=\dfrac{1}{8}x^3-\dfrac{9}{4}x^2+\dfrac{27}{2}x -27$
$(2x+1)^3$
$=8x^3+12x^2+6x+1$
$(2x+1)^3$
$=8x^3+12x^2+6x+1$
$\left (3x-\dfrac{1}{2} \right )^2$
$=9x^2-3x+\dfrac{1}{4}$