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25 tháng 5 2022
a: \(A=\dfrac{3x^2+4x^2y}{x^2}-\dfrac{10xy+15xy^2}{5y}\)
\(=3+4y-2x-3xy\)
\(=3+4\cdot\left(-5\right)-2\cdot2-3\cdot2\cdot\left(-5\right)\)
\(=3-20-4+30=10-1=9\)
b: \(B=\dfrac{18a^4-27a^3}{9a^2}-10a^3:5a\)
\(=2a^2-3a-10a^3:5a\)
\(=2a^2-3a-2a^2=-3a=-3\cdot\left(-8\right)=24\)
c: \(C=\dfrac{8x^3-4x^2}{2x^2}-\dfrac{4x^2-3x}{x}+2x\)
\(=4x-2-4x+3+2x\)
=2x+1=-2+1=-1
AV
3
DH
16 tháng 8 2017
a, \(\left(25y^2+\dfrac{1}{9}x^2+\dfrac{5}{3}xy\right)\left(5y-\dfrac{1}{3}x\right)\)
Nó tự phân tích cho rồi nha bạn!
b, \(-125y^3-\dfrac{1}{27}x^3\)
\(=\left(-5y\right)^3-\left(\dfrac{1}{3}x\right)^3\)
\(=\left(-5y-\dfrac{1}{3}x\right)\left(25y^2-\dfrac{5}{3}xy+\dfrac{1}{9}x^2\right)\)
Chúc bạn học tốt!!!
16 tháng 8 2017
Câu a :
\(\left(25y^2+\dfrac{1}{9}x^2+\dfrac{5}{3}xy\right)\left(5y-\dfrac{1}{3}x\right)\)
\(=\left(5y+\dfrac{1}{3}x\right)^2\left(5y-\dfrac{1}{3}x\right)\)
Câu b :
\(-125y^3-\dfrac{1}{27}x^3\)
\(=\left(-5y\right)^3-\left(\dfrac{1}{3}x\right)^3\)
\(=\left(-5y-\dfrac{1}{3}x\right)\left(25y^2+\dfrac{5}{3}xy+\dfrac{1}{9}x^2\right)\)
16 tháng 6 2018
a) 2x(y-2009)+5y(y-2009)
=(y-2009)(2x+5y)
b) 35x(y-8)-14y(8-y)
=35x(y-8)+14y(y-8)
=7(y-8)(5x+2y)
c) 15x^2 +10xy =5x(3x+2y)
d)24x-18y+30= 6(4x+3y+10)
e) x^2 +14x+49
= x^2 +2.7.x+ 7^2
=(x+7)^2
i) x^2 -x - y^2 - y
=(x^2 -y^2)-(x+y)
=(x-y)(x+y)-(x+y)
=(x+y)(x-y-1)
k) x^2 -2xy+y^2 -z^2
=(x^2 -2xy+y^2) -z^2
=(x-y)^2 -z^2
= (x-y-z)(x-y+z)
9 tháng 8 2018
a) \(2x\left(y-2009\right)+5y\left(y-2009\right)\) \(=\left(y-2009\right)\left(2x+5y\right)\)
b) \(35x(y-8)-14y(8-y)\) \(=35x\left(y-8\right)+14y\left(y-8\right)\)
\(=\left(y-8\right)\left(35x+14y\right)\)
\(=\left(y-8\right).7\left(5x+2y\right)\)
c) \(15x^2+10xy=5x\left(3x+2y\right)\)
d) \(24x-18y+30=3\left(8x-6y+10\right)\)
e) \(x^2+14x+49=x^2+2.7.x+7^2\)
\(=\) \((x+7)^2\)
g) \(27x^3+y^3\) \(=\left(3x+y\right)\left(9x^2-3xy+y^2\right)\)
h) \(8x^3-\dfrac{1}{125}y^3=\left(2x-\dfrac{1}{5}y\right)\left(4x^2+\dfrac{2}{5}xy+\dfrac{1}{25}y^2\right)\)
i) \(x^2-x-y^2-y=\left(x^2-y^2\right)-\left(x+y\right)\)
\(=\left(x-y\right)\left(x+y\right)-\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-1\right)\)
k) \(x^2-2xy+y^2-z^2=\left(x^2-2xy+y^2\right)-z^2\)
\(=\left(x-y\right)^2-z^2\)
\(=\left(x-y-z\right)\left(x-y+z\right)\)
- HỌC TỐT NHA BẠN YÊU ^^ -
2 tháng 11 2017
a/ 5x2y - 2xy
= xy.(5x-2)
b/ x2 - 6x + 9
= x2 - 2.3.x + 32
= (x-3)2
c/ 8x3 - 27
= (2x)3 - 33
= (2x - 3).[(2x)2 - 2x.3 + 32]
= (2x-3).(4x2 - 6x + 9)
d/ x2 - 2x - 25y2 + 1
= (x2 - 2x + 1) - 25y2
= (x-1)2 - (5y)2
= (x-1-5y).(x-1+5y)
e/ 6x2 - x - 5
= 6x2 + 6x - 5x - 5
= 6x.(x+1) - 5.(x+1)
= (x+1).(6x-5)
f/ (2x -y).(x+3) - 5.(y-2x)
= (2x-y).(x+3) + 5.(2x-y)
= (2x-y).(x+3+5)
= (2x-y).(x+8)
g/ (x+y)2 - z2
= (x+y-z).(x+y+z)
k/ x3 - 4x2 + 4x
= x.(x2 - 4x + 4)
= x.(x2 - 2.x.2 + 22)
= x.(x-2)2
m/ 5x2 - x + y - 5y2
= 5x2 - 5y2 - (x-y)
= 5.(x2 - y2) - (x-y)
= 5.(x+y).(x-y) - (x-y)
= (x-y).[5(x+y) - 1]
i/ x2 + 9x - 10
= x2 - x + 10x - 10
= x.(x-1) + 10.(x-1)
= (x-1).(x+10)
A
2 tháng 11 2017
a)5x2y-2xy=xy(5x-2)
b)x2-6x+9=x2-2.x.3+32=(x-3)2
c)8x3-27=(2x)3-33=(2x-3)(4x2+6x+9)
d)x2-2x-25y2+1=(x2-2x+1)-25y2=(x-1)2-25y2
=(x-1-5y)(x-1+5y)
e)6x2-x-5=6x2-6x+5x-5=(6x2-6x)+(5x-5)=6x(x-1)+5(x-1)=(x-1)(6x+5)
f)(2x-y)(x+3)-5(y-2x)=(2x-y)(x+3)-5(2x-y)=(2x-y)(x+3-5)=(2x-y)(x-2)
g)(x+y)2-z2=(x+y+z)(x+y-z)
k)x3-4x2+4x=x(x2-4x+4)=x(x-2)2
m)5x2-x+y-5y2=(5x2-5y2)-(x-y)=5(x2-y2)-(x-y)=5(x-y)(x+y)-(x-y)
=5(x-y)(x+y+1)
i)x2+9x-10=x2-x+10x-10=(x2-x)+(10x-10)=x(x-1)+10(x-1)=(x-1)(x+10)
NN
23 tháng 11 2017
a) \(x^2-y^2-5x-5y\)
\(=\left(x^2-y^2\right)-\left(5x+5y\right)\)
\(=\left(x-y\right)\left(x+y\right)-5\left(x+y\right)\)
\(=\left(x+y\right)\left(x-y-5\right)\)
b) \(5x^3-5x^2y-10x^2+10xy\)
\(=\left(5x^3-5x^2y\right)-\left(10x^2-10xy\right)\)
\(=5x^2\left(x-y\right)-10x\left(x-y\right)\)
\(=\left(x-y\right)\left(5x^2-10x\right)\)
\(=5x\left(x-y\right)\left(x-2\right)\)
c) \(x^3-2x^2-x+2\)
\(=\left(x^3-2x^2\right)-\left(x-2\right)\)
\(=x^2\left(x-2\right)-\left(x-2\right)\)
\(=\left(x-2\right)\left(x^2-1\right)\)
\(=\left(x-2\right)\left(x-1\right)\left(x+1\right)\)
d) \(-y^2+2xy-x^2+3x-3y\)
\(=-\left(y^2-2xy+x^2\right)+\left(3x-3y\right)\)
\(=-\left(y-x\right)^2+3\left(x-y\right)\)
\(=-\left(x-y\right)^2+3\left(x-y\right)\)
\(=\left(x-y\right)\left[-\left(x-y\right)+3\right]\)
\(=\left(x-y\right)\left(-x+y+3\right)\)
g) \(4x^2-8x+3\)
\(=4x^2-6x-2x+3\)
\(=\left(4x^2-6x\right)-\left(2x-3\right)\)
\(=2x\left(2x-3\right)-\left(2x-3\right)\)
\(=\left(2x-3\right)\left(2x-1\right)\)
h) \(2x^2-5x-7\)
\(=2x^2+2x-7x-7\)
\(=\left(2x^2+2x\right)-\left(7x+7\right)\)
\(=2x\left(x+1\right)-7\left(x+1\right)\)
\(=\left(x+1\right)\left(2x-7\right)\)
k) \(x^4+4\)
\(=x^4+4x^2+4-4x^2\)
\(=\left[\left(x^2\right)^2+2.x^2.2+2^2\right]-4x^2\)
\(=\left(x^2+2\right)^2-\left(2x\right)^2\)
\(=\left(x^2+2-2x\right)\left(x^2+2+2x\right)\)
21 tháng 9 2020
a) Ta có: \(5x^2-10xy+5y^2-20z^2\)
\(=5\left(x^2-2xy+y^2-4z^2\right)\)
\(=5\left[\left(x-y\right)^2-\left(2z\right)^2\right]\)
\(=5\left(x-y-2z\right)\left(x-y+2z\right)\)
b) Ta có: \(x^2-8x+15\)
\(=x^2-3x-5x+15\)
\(=x\left(x-3\right)-5\left(x-3\right)\)
\(=\left(x-3\right)\left(x-5\right)\)
c) Ta có: \(2x^2-5xy+3y^2\)
\(=2x^2-2xy-3xy+3y^2\)
\(=2x\left(x-y\right)-3y\left(x-y\right)\)
\(=\left(x-y\right)\left(2x-3y\right)\)
d) Ta có: \(16y^3-2x^3-6x\left(x+1\right)-2\)
\(=16y^3-2x^3-6x^2-6x-2\)
\(=2\left[8y^3-x^3-3x^2-3x-1\right]\)
\(=2\left[\left(2y\right)^3-\left(x^3+3x^2+3x+1\right)\right]\)
\(=2\left[\left(2y\right)^3-\left(x+1\right)^3\right]\)
\(=2\left(2y-x-1\right)\left[\left(2y\right)^2+2y\left(x+1\right)+\left(x+1\right)^2\right]\)
\(=2\left(2y-x-1\right)\left(4y^2+2xy+2y+x^2+2x+1\right)\)
ae giải giúp mình
( 2x - 5y )( 4x2 + 10xy + 25y2 )
=( 2x )3 - ( 5y )3
= 8x3 - 125y3