a) 5x-15y=5x-3.5.y=5(x-3y)

c) 14xy(xy+28x)

d) \(\dfrac{2}{7}\left(3x-1\right)\left(x-1\right)\)

e) (x-1)³

f) (x+y-2x)(x+y+2x)=(y-x)(3x+y)

g) (3x+\(\dfrac{1}{2}\))(9x²+\(\dfrac{3}{2}x\)+\(\dfrac{1}{4}\))

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

2a)

(x+1)(x²+2x)=0

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

\(\left[{}\begin{matrix}x+1=0\\x=0\\x+2=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=-1\\x=0\\x=-2\end{matrix}\right.\)

2.a là x=0 , x=-1, x=-2
2.b là x=2/3 , x=-5

Trả lời tội ghê đó bạn nhưng mk gửi một bài mà sao bạn trả lời một câu vậy bạn nhưng dù sao vẫn cảm on nha

pạn ơi pạn đã lm đk chưa? nếu lm đk oy cho mk xem cách lm bài 2 nhé. cảm ơn pạn nhìu lắm

Bài 8:

b. 1+8x⁶y³ = 1³+2³(x²)³y³ = 1³+(2x²y)³

= (1+2x²y)(1-2x²y+4x⁴y²)

e. 27x³+\(\dfrac{y^3}{8}\)\(=\left(3x\right)^3+\left(\dfrac{y}{2}\right)^3\)

= (3x+\(\dfrac{y}{2}\))(9x²-\(\dfrac{3xy}{2}\)+\(\dfrac{y^2}{4}\))

Bài 9:

c. 1- 9x +27x² -27x³ = 1³-3.1².3x+3.(3x)²-(3x)³

= (1-3x)³

d. x³+\(\dfrac{3}{2}x^2\)+\(\dfrac{3}{4}x+\dfrac{1}{8}\) = x³+\(3x^2.\dfrac{1}{2}\)+\(3x.\dfrac{1}{4}+\left(\dfrac{1}{2}\right)^3\)

= (x+\(\dfrac{1}{2}\))³

f. x² - 2xy +y² -4m² +4m.n - n² = (x² - 2xy +y²)-((2m)² -2.2m.n + n²)

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

Đăng ít thôi.

~ bt làm hăm giúp mình câu 2+3

a) \(\dfrac{1}{8}x^3y^3-27=\left(\dfrac{1}{2}xy\right)^3-3^3=\left(\dfrac{1}{2}xy-3\right)\left(\dfrac{1}{4}x^2y^2+\dfrac{1}{6}xy+9\right)\)

b)\(\dfrac{8}{125}x^3+27y^3=\left(\dfrac{2}{5}x\right)^3+\left(3y\right)^3=\left(\dfrac{2}{5}x+3y\right)\left(\dfrac{4}{25}x^2-\dfrac{6}{5}xy+9y^2\right)\)

c) \(0.008x^6-27y^3=\left(0.2x^2\right)^3-\left(3y\right)^3=\left(0.2x^2-3y\right)\left(0.04x^4+\dfrac{3}{5}x^2y+9y^2\right)\)

d)\(\left(2x+y\right)^3-\left(x-y\right)^3=\left(2x+y-x+y\right)[\left(2x+y\right)^2+\left(2x+y\right)\left(x-y\right)+\left(x-y\right)^2]\\ =\left(x+2y\right)\left(4x^2+4xy+y^2+2x^2-2xy+xy-y^2+x^2-2xy+y^2\right)\\ =\left(x+2y\right)\left(6x^2+xy+y^2\right)\)

Bài 1:

a) \(\dfrac{1}{8}x^3y^3-27\)

\(=\left(\dfrac{1}{2}xy\right)^3-3^3\)

\(=\left(\dfrac{1}{2}xy-3\right)\left[\left(\dfrac{1}{2}xy\right)^2+\dfrac{1}{2}xy.3+3^2\right]\)

\(=\left(\dfrac{1}{2}xy-3\right)\left(\dfrac{1}{4}xy+\dfrac{3}{2}xy+9\right)\)

\(=\left(\dfrac{1}{2}xy-3\right)\left(\dfrac{7}{4}xy+9\right)\)

b) \(\dfrac{8}{125}x^3+\dfrac{1}{8}y^3\)

\(=\left(\dfrac{2}{5}x\right)^3+\left(\dfrac{1}{2}y\right)^3\)

\(=\left(\dfrac{2}{5}x+\dfrac{1}{2}y\right)\left[\left(\dfrac{2}{5}x\right)^2-\dfrac{2}{5}x.\dfrac{1}{2}y+\left(\dfrac{1}{2}y\right)^2\right]\)

\(=\left(\dfrac{2}{5}x+\dfrac{1}{2}y\right)\left(\dfrac{4}{25}x-\dfrac{1}{5}xy+\dfrac{1}{4}y\right)\)

c) \(0.008x^6-27y^3\)

\(=\left(\dfrac{1}{5}x^2\right)^3-\left(3y\right)^3\)

\(=\left(\dfrac{1}{5}x^2-3y\right)\left[\left(\dfrac{1}{5}x^2\right)^2+\dfrac{1}{5}x^2.3y+\left(3y\right)^2\right]\)

\(=\left(\dfrac{1}{5}x^2-3y\right)\left(\dfrac{1}{25}x^4+\dfrac{3}{5}x^2y+9y^2\right)\)

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

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

\(=\left(2x+y-x+y\right)\left(4x^2+4xy+y^2+2x^3-2xy+xy-y^2+x^2-2xy+y^2\right)\)

\(=\left(x-2y\right)\left(4x^2+2x^3+xy\right)\)

a) \(=2xy^2\left(x^2+8x+15\right)\)

\(=2xy^2\left[\left(x^2+8x+16\right)-1\right]\)

\(=2xy^2\left[\left(x+4\right)^2-1\right]\)

\(=2xy^2\left(x+4+1\right)\left(x+4-1\right)\)

\(=2xy^2\left(x+5\right)\left(x-3\right)\)

mấy câu sau tự làm nha :*

b,=(x^2-10x+25)-4

  =(x-5)^2-2^2

  =(x-5-2)(x-5+2)

  =(x-7)(x-3)

1) \(-4x^5\left(x^3-4x^2+7x-3\right)\)

\(=-4x^8+16x^7-28x^6+12x^5\)

2) \(3x^4\left(-2x^3+5x^2-\dfrac{2}{3}x+\dfrac{1}{3}\right)\)

\(=-6x^7+15x^6-2x^5+x^4\)

3) \(-5x^2y^4\left(3x^2y^3-2x^3y^2-xy\right)\)

\(=-15x^4y^7+10x^5y^6+5x^3y^5\)

4) \(4x^3y^2\left(-2x^2y+4x^4-3y^2\right)\)

\(=-8x^5y^3+16x^7y^2-12x^3y^4\)

mình học lớp 4

$a)$ \(x^{12}:\left(-x\right)^6\)

\(=x^{12}:x^6\)

\(=x^{12-6}\)

\(=x^6\)

$b) $ \(\left(-x\right)^7:\left(-x\right)^5\)

\(=\left(-x\right)^{7-5}\)

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

\(=x^2\)

$c)$ \(5x^2y^4:10x^2y\)

\(=\dfrac{1}{2}y^3\)

$e)$ \(\left(-xy\right)^{14}:\left(-xy\right)^7\)

\(=\left(-xy\right)^{14-7}\)

\(=\left(-xy\right)^7\)

Các câu còn lại tương tự nha bạn!