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18 tháng 7 2016

(x+y+z)(x²+y²+z²-xy-yz-xz)

Có thể xem trên wikipedia với từ khóa 7 HDT đáng nhớ mục liên quan nhé bạn​

\(x^3+y^3+z^3-3xyz\)

\(=x^3+y^3+z^3-xyz-xyz-xyz\)

\(=\left(x+y+z\right)\left(x^2+y^2+z^2-xy-yz-xz\right)\)

26 tháng 11 2021

\(x^3-y^3+2x^2+2xy\)

\(=x\left(x^2-y^2+2x+2y\right)\)

\(=\)\(x\left[\left(x+y\right)\left(x-y\right)+2\left(x+y\right)\right]\)

\(=x\left(x+y\right)\left(x-y+2\right)\)

26 tháng 11 2021

x^3 - y^3 + 2x^2 + 2xy

= x [ ( x^2 - y^2 ) + ( 2x + 2y ) ]

= x [ ( x + y ) ( x - y ) + 2 ( x + y ) ]

= x ( x + y ) ( x - y + 2 )

AH
Akai Haruma
Giáo viên
4 tháng 2 2023

Câu 1:

$x^2+4y^2+4xy-16=[x^2+(2y)^2+2.x.2y]-16$

$=(x+2y)^2-4^2=(x+2y-4)(x+2y+4)$

Câu 2:

$x^3+x^2+y^3+xy=(x^3+y^3)+(x^2+xy)$

$=(x+y)(x^2-xy+y^2)+x(x+y)=(x+y)(x^2-xy+y^2+x)$

4 tháng 2 2023

Câu 1:

\(x^2+4y^2+4xy-16\)

\(=\left(x+2y\right)^2-16\)

\(=\left(x+2y+4\right)\left(x+2y-4\right)\)

Câu 2:

\(x^3+x^2+y^3+xy\)

\(=\left(x^3+y^3\right)\left(x^2+xy\right)\)

\(=\left(x+y\right)\left(x^2-xy+y^2\right)+x\left(x+y\right)\)

\(=\left(x+y\right)\left(x^2-xy+y^2+x\right)\)

24 tháng 12 2018

x + y + z 3 - z 3 - y 3 - z 3 =   ( x   +   y )   +   z 3   –   x 3   –   y 3   –   z 3 =   ( x   +   y ) 3   +   3 ( x   +   y ) 2 z   +   3 ( x   +   y ) z 2   +   z 3   –   x 3   –   y 3   –   z 3 =   x 3   +   y 3   +   3 x y ( x   +   y )   +   3 ( x   +   y ) 2 z   +   3 ( x   +   y ) z 2   –   x 3   –   y 3 (   v ì   z 3   –   z 3   =   0   ;   3 x 2 y   +   3 x y 2   =   3 x y   ( x   +   y )   ) =   3 x y . ( x +   y )   +   3 (   x +   y ) 2 . z   +   3 ( x +   y ) . z 2 =   3 ( x   +   y ) [ x y   +   ( x   +   y ) z   +   z 2 ] =   3 ( x   +   y ) [ x y   +   x z   +   y z   +   z 2 ] =   3 ( x   +   y ) [ x ( y   +   z )   +   z ( y   +   z ) ] =   3 ( x   +   y ) ( y   +   z ) ( x   +   z )

11 tháng 12 2017

x 3  +  y 3  +  z 3  – 3xyz = x + y 3  – 3xy(x + y) +  z 3  – 3xyz

      = [  x + y 3  +  z 3 ] - [ 3xy.(x+ y) + 3xyz]

      = [ x + y 3  +  z 3 ] – 3xy(x + y + z)

      = (x + y + z)[ x + y 2  – (x + y)z +  z 2 ] – 3xy(x + y + z)

      = (x + y + z)( x 2  + 2xy + y 2  – xz – yz + z 2  – 3xy)

      = (x + y + z)( x 2  +  y 2  +  z 2  – xy – xz - yz)

6 tháng 2 2022

a) `-3/5  + (-7)/24 + 19/24`

`= -3/5 + ( -7/24 + 19/24)`

`= -3/5 + 1/2`

`= -6/10 + 5/10`

`=-1/10`

b) `-5/9. 2/13 + (-5/9) . 11/13 + 1 5/9`

`= -5/9 ( 2/13 + 11/13) + 1  + 5/9`

`= -5/9 . 1 + 1 + 5/9`

`=-5/9 + 5/9 +1`

`= 1`

c) `(-5/24 + 0,75 + 7/12) : (-2 1/8)`

`= (-5/24 + 18/24 + 14/24) : (-17/8)`

`= 9/8 . (-8/17)`

`=-9/17`

18 tháng 6 2019

\(\frac{x+2}{5}=\frac{3x-4}{-3}\)

\(\Rightarrow\left(x+2\right).\left(-3\right)=\left(3x-4\right).5\)

\(\Rightarrow-3x-6=15x-20\)

Từ đây chuyển vế đổi dấu là xong nhé!

x+2/5=3x-4/-3

<=> (x+2).3=(3x-4).-3              (nhân chéo  2 vế)

<=> 3x+6=-9x+12

<=>12x=6

<=>x=6/12=1/2

vậy x=1/2

học tốt

11 tháng 9 2023

Bài 5: 

1. There are a few students taking part in the event     

→ There aren't many students taking part in the event.

2. If he doesn't work hard, he will lose his job     

→ Unless he works hard, he will lose his job.

3. Let's write about the three Rs ?         

→ Why  don't we write about the three Rs?

4. Learning about recyking is fun           

→ It's fun to learn about recycling.

5. It's not good to throw old clothes away               

→ You  shouldn't throw old clothes away

Xếp từ thành câu

Bài 1

1. they / to / movies / do / how / go / the / often ?   

→ How often do they go to the movies?

2. your eyes / swimming / should / when  goggles / you / you / go / wear / to protect

→ When you go swimming, you should wear goggles to protect your eyes.

3. usually / his  / swimming / with / friends / he / goes       

→ He usually goes swimming with his friends.

4. go / do / weekend / on / always / fishing / parents / their ?   

→ Do their parents always go fishing on the weekend?

5. camping / they / go / do / sometimes

→  Sometimes they go camping.

6. what / TV / you / do / on / sports / watch?

→ What sports do you watch on TV?

Bài 2

1. Our / important / an / sports and games / in play / lives / part       

→ Sports and games play an important part in our lives.       

2. players / how / match / there / in / many / are / football / a ?   

→ How many players are there in a football match?

3. by / she / to keep / every day / tries / fit / jogging 

→ She tries to keep fit by jogging every day.

4. yesterday / who / play / football / you / did / with ?

→ Who did you play football with yesterday?

5. sports / building / physical and strength / necessary / are / for

→ Sports are necessary for building physical strength.

6. to switch / before / go / don't / the TV / off / you / forget / to bed

→ Don't forget to switch off the TV before you go to bed.

7. Sunday / I / usually / friends / swimming / on / go / mornings / with / my

→ On Sunday mornings, I usually go swimming with my friends.

8. match / you / on / the / did / television / last night / watch / basketball / the ?

→ Did you watch the basketball match on television last night? 

20 tháng 8 2023

\(8x^3+12x^2y+6xy^2+y^3-z^3\)

\(=\left(2x+y\right)^3-z^3\)

\(=\left(2x+y-z\right)\left[4x^2+z\left(2x+y\right)+z^2\right]\)

20 tháng 8 2023

a, 8a3 - 36a2 +54ab2 - 27b3

=(8a3-36a2b +54ab2 - 27b3)

=(2a-3b)2

=(2a-3b)(2a-3b)(2a-3b)

b, 8x3 + 12x2y + 6xy2 + y3 - z 3

=(8x3 + 12x2y + 6xy2 + y3) - z3

=(2x + y)3 - y3

=(2x + y +z) . [ (2x + Y)2 + 2(2x + y)+ z2

= (2x + y + z)(4x2 + 4xy + y2 + 4x + 2y + z2

 

23 tháng 7 2021

( x + y + z)3 - x3 - y3 - z3=x3+y3+z3+3(a+b)(a+c)(b+c)- x3 - y3 - z3

                                              = 3(a+b)(b+c)(a+c)