1.

\(a,\left(-xy\right)\left(-2x^2y+3xy-7x\right)\)

\(=2x^3y^2-3x^2y^2+7x^2y\)

\(b,\left(\dfrac{1}{6}x^2y^2\right)\left(-0,3x^2y-0,4xy+1\right)\)

\(=-\dfrac{1}{20}x^4y^3-\dfrac{1}{15}x^3y^3+\dfrac{1}{6}x^2y^2\)

\(c,\left(x+y\right)\left(x^2+2xy+y^2\right)\)

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

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

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

\(=\left(x-y\right)^3\)

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

2.

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

\(=x^3-y^3\)

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

\(=x^3+y^3\)

\(c,\left(4x-1\right)\left(6y+1\right)-3x\left(8y+\dfrac{4}{3}\right)\)

\(=24xy+4x-6y-1-24xy-4x\)

\(=\left(24xy-24xy\right)+\left(4x-4x\right)-6y-1\)

\(=-6y-1\)

#Toru

ở đây lp 9 mak cn xưng em =_=

1.

a.

x(y-1)-(y-1)=0

(x-1)(y-1)=0

x=1

y=1

b.x,y khác không

(x+y)/xy=1/2

2x+2y=xy

x(2-y)-2(2-y)=4

(x-2)(y-2)=4

x-2={-4,-2,1,4}=>x={-2,0,3,6}

y-2={-1,-2,4,1}=>y={3,0,6,3}

a) \(\left(2x^3-x^2+5x\right):x\)

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

\(=\dfrac{x\left(2x^2-x+5\right)}{x}\)

\(=2x^2-x+5\)

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

\(=\dfrac{3x^4-2x^3+x^2}{-2x}\)

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

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

\(=-\dfrac{3}{2}x^3+x^2-\dfrac{1}{2}x\)

c) \(\left(-2x^5+3x^2-4x^3\right):2x^2\)

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

\(=\dfrac{2x^2\left(-x^3+\dfrac{3}{2}-2x\right)}{2x^2}\)

\(=-x^3-2x+\dfrac{3}{2}\)

d) \(\left(x^3-2x^2y+3xy^2\right):\left(-\dfrac{1}{2}x\right)\)

\(=\dfrac{x^3-2x^2y+3xy^2}{-\dfrac{1}{2}x}\)

\(=\dfrac{\dfrac{1}{2}x\left(2x^2-4xy+6y^2\right)}{-\dfrac{1}{2}x}\)

\(=-\left(2x^2-4xy+6y^2\right)\)

\(=-2x^2+4xy-6y^2\)

e) \(\left[3\left(x-y\right)^5-2\left(x-y\right)^4+3\left(x-y\right)^2\right]:5\left(x-y\right)^2\)

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

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

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

f) \(\left(3x^5y^2+4x^3y^3-5x^2y^4\right):2x^2y^2\)

\(=\dfrac{3x^5y^2+4x^3y^3-5x^2y^4}{2x^2y^2}\)

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

\(=\dfrac{3}{2}x^3+2xy-\dfrac{5}{2}y^2\)

a,63

b,54

c,3

d,410

e,270

f,110

a, 3(x+y)

Thay x=6,y=15 vào bt trên ta có:

3(6+15) = 3.21 =63

b, 2(2x+y)

Thay x=6, y=15 vào bt trên ta có: 

2(2.6+15) = 2(12+15) = 2.27 = 54

c, \(\frac{x}{2}\)

Thay x=6 vào bt trên ta có:

6:2=3

các ý khác bạn lạm tương tự như thế này nhé

a. vô nghiệm  vì tổng hai số dương chỉ bằng ko khi chúng đồng thời bằng 0

b. tổng 3 số dưng =0 khi dồng thời cả 3 bằng 0

vậy x=1; y=-1; z=1

c.tổng 3 số dưng luông  lớn hơn bằng ko

vậy x=1/3; y=2; z=1

d tương tự 

x-z=0

x+y=0

z+1/4=0

.............

z=-1/4

x=-1/4

y=1/4

Cac ban lam chi tiet giup minh voi 

where is đề

a) 20x-5y=5(4x-y)

b) 5x(x-1)-3x(x-1)=(5x-3x)(x-1)=2x(x-1)

c) x(x+y)-6x-6y=x(x+y)-(6x+6y)=x(x+y)-6(x+y)=(x-6)(x+y)

d) 6x³-9x²=3x²(2x-3)

e) 4x²y - 8xy² + 10x²y²=2xy(2x-4y+5xy)

g) 20x²y-12x³=4x²(5y-3x)

h) 8x⁴+ 12x²y⁴- 16x³y⁴ = 4x²(2x²+3y⁴-4xy⁴)

k) 4xy² + 8xyz=4xy(y+2z)

l) 3x(x + 1) - 5y( x + 1 )=(x+1)(3x-5y)

m) 4x²-1=(2x-1)(2x+1)

o) 9-(x-y)²=(3-x+y)(3+x-y)

p) x³+27=(x+3)(x²+3x+9)

n) (x-y)²-4=(x-y-2)(x-y+2)

r) x⁴ + 2x² + 1=(x⁴+x²)+(x²+1)=x²(x²+1)+(x²+1)=(x²+1)²

s) 4x²  - 12xy + 9y²  = (2x-3y)²

t) x² - x - y² - y =(x²-y²)-(x+y)=(x-y)(x+y)-(x+y)=(x+y)(x-y-1)

v) x³ - x + y³ - y = (x³+y³)-(x+y)=(x+y)(x²-xy+y²)-(x+y)=(x+y)(x²-xy+y²-1)

a: \(20x-5y=5\left(4x-y\right)\)

b: \(5x\left(x-1\right)-3x\left(x-1\right)=2x\left(x-1\right)\)

c: \(x\left(x+y\right)-6x-6y=\left(x+y\right)\left(x-6\right)\)

d: \(6x^3-9x^2=3x^2\left(x-3\right)\)

e: \(4x^2y-8xy^2+10x^2y^2=2xy\left(2x-4y+5xy\right)\)