1) x³ - 1 +x - x²

2) (a² + 9)² - 36a²

3) ( x² + 1)² - 4x²

4) ( 4a² + 1/4)² - 4a²

5) 81 - (x² + 6x)²

6) 16a² - (a² + 4)²

7) 1/4 ( a + 1)² - 4/9 ( a-2)²

8) ( x² + xy)² - (y² + xy)²

9) 12a²b² - 3( a² +b²)²

10) 4x²y² - ( x² + y² - a²)²

11) ( a+b+c)² + ( a+b-c)² - 4c²

12) x³ - 1 + 5x² - 5 +3x - 3

13) ( x - y)² + 4(x-y) + 4

14) x² -2x( 3x+1) + (3x+1)²

15) x⁴ + 2x²(2x+1) + ( 2x+1)²

^{hok tốt}

bn nhắn j vậy ????????

\(\frac{1}{4}x^3x\left(-8abxy^2\right)\)

\(=\frac{1}{4}-x^4.\left(-8x^4xaby^2\right)\)

\(=\frac{1}{4}-\left(-8x^5aby^2\right)\)

\(=\frac{1}{4}+8x^5aby^2\)

bạn không ghi rõ đầu bài nên mik làm như này , ko bik có đúng đầu bài ko ... ^-^

+) : Thu gọn đa thức rồi tính 

\(\frac{1}{4}-x^3.x\left(-8.a.b.x.y^2\right)\)

= \(\left[\frac{1}{4}.\left(-8\right)\right].\left(x^3.x.x\right).a.b.y^2\\ =-2.x^5.a.b.y^2\)

= \(-2x^5aby^2\)

+) xác định hệ số và phần biến

Phần hệ số là : \(-2\)

Phần biến là : \(x^5aby^2\)

XONG CHÚC BẠN HỌC GIỎI NHÉ....CỐ LÊN ! ^-^

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                                      H

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                                                                       Ó

a: =>x-2/5=3/4:1/3=3/4*3=9/4

=>x=9/4+2/5=45/20+8/20=53/20

b: =>x-2/3=7/3:4/5=7/3*5/4=35/12

=>x=35/12+2/3=43/12

c: 1/3(x-2/5)=4/5

=>x-2/5=4/5*3=12/5

=>x=12/5+2/5=14/5

d: =>2/3x-1/3-1/4x+1/10=7/3

=>5/12x-7/30=7/3

=>5/12x=7/3+7/30=77/30

=>x=77/30:5/12=154/25

e: \(\Leftrightarrow x\cdot\dfrac{3}{7}-\dfrac{2}{7}+\dfrac{1}{2}-\dfrac{5}{4}x+\dfrac{5}{2}=0\)

=>\(x\cdot\dfrac{-23}{28}=\dfrac{2}{7}-3=\dfrac{-19}{7}\)

=>x=19/7:23/28=76/23

f: =>1/2x-3/2+1/3x-4/3+1/4x-5/4=1/5

=>13/12x=1/5+3/2+4/3+5/4=257/60

=>x=257/65

i: =>x^2-2/5x-x^2-2x+11/4=4/3

=>-12/5x=4/3-11/4=-17/12

=>x=17/12:12/5=85/144

1: 

\(\Leftrightarrow\left(x^2+5x+6\right)\left(x^2+5x+4\right)=24\)

\(\Leftrightarrow\left(x^2+5x\right)^2+10\left(x^2+5x\right)=0\)

\(\Leftrightarrow x^2+5x=0\)

=>x=0 hoặc x=-5

3: \(\Leftrightarrow\left(x^2+x+6\right)\left(x^2+x-2\right)=0\)

=>(x+2)(x-1)=0

=>x=-2 hoặc x=1

a) \(x-\dfrac{3}{4}=6\times\dfrac{3}{8}\)

\(x-\dfrac{3}{4}=\dfrac{9}{4}\)

=> \(x=\dfrac{9}{4}+\dfrac{3}{4}=3\)

b) \(\dfrac{7}{8}:x=3-\dfrac{1}{2}\)

\(\dfrac{7}{8}:x=\dfrac{5}{2}\)

=> \(x=\dfrac{7}{8}:\dfrac{5}{2}=\dfrac{7}{20}\)

c) \(x+\dfrac{1}{2}\times\dfrac{1}{3}=\dfrac{3}{4}\)

\(x+\dfrac{1}{6}=\dfrac{3}{4}\)

=> \(x=\dfrac{3}{4}-\dfrac{1}{6}=\dfrac{7}{12}\)

d) \(\dfrac{3}{2}\times\dfrac{4}{5}-x=\dfrac{2}{3}\)

\(\dfrac{6}{5}-x=\dfrac{2}{3}\)

=> \(x=\dfrac{6}{5}-\dfrac{2}{3}=\dfrac{8}{15}\)

e) \(x\times3\dfrac{1}{3}=3\dfrac{1}{3}:4\dfrac{1}{4}\)(?)

\(x\times\dfrac{10}{3}=\dfrac{40}{51}\)

=> \(x=\dfrac{40}{51}:\dfrac{10}{3}=\dfrac{4}{17}\)

f) \(5\dfrac{2}{3}:x=3\dfrac{2}{3}-2\)

\(\dfrac{17}{3}:x=\dfrac{5}{3}\)

=> \(x=\dfrac{17}{3}:\dfrac{5}{3}=\dfrac{17}{5}\)

a: =>x-3/4=18/8=9/4

=>x=9/4+3/4=12/4=3

b: =>7/8:x=5/2

=>x=7/8:5/2=7/8*2/5=14/40=7/20

c: x+1/2*1/3=3/4

=>x+1/6=3/4

=>x=3/4-1/6=9/12-2/12=7/12

d: =>12/10-x=2/3

=>6/5-x=2/3

=>x=6/5-2/3=18/15-10/15=8/15

e: =>x*10/3=10/3:17/4=10/3*4/17

=>x=4/17

f: =>17/3:x=13/3-5/2=26/6-15/6=11/6

=>x=17/3:11/6=17/3*6/11=34/11