\(2x\left(x^2-7x-3\right)=2x^3-14x-6x\)

\(4xy^2\left(-2x^3+y^2-7xy\right)=-8x^4y^2+4xy^5-28x^2y^3\)

giúp mình nha mình cần gấp, cảm ơn mọi người trước

a) (2x+3)²

=4x^2+12x+9

b) (x-2/5)³

=x^3-1.2x^2+0.48x-0.064

c) (4x²+1)³

=(4x^2)^3+12x^4+12x^2+1

\(a,2x\left(3x^2+1\right)=6x^3+2x\)

\(b,\left(2x^3-5x^2+6x\right):2=x^3-\dfrac{5}{2}x^2+3x\)

\(c,\left(x-3\right)\left(x+5\right)-x\left(x+2\right)=x^2+5x-3x-15-x^2-2x=-15\)

\(a,=4x^2+4x+1\\ b,=9-12y+4y^2\\ c,=\dfrac{x^2}{4}-xy+y^2\\ d,=\dfrac{25}{4}-5x+x^2\\ e,=4x^2+32xy+64y^2\\ f,=9x^2-30xy+25y^2\)

a. (2x + 1)² 

= 4x² + 4x + 1

b. (3 - 2y)²

= 9 - 12y + 4y²

- Các câu còn lại bn dung CT: (A + B)² = A² + 2AB + B² và (A - B)² = A² - 2AB + B² để tính tiếp nha, phân số cũng đc tính.)

a) 4x^2 + 4x + 1

b) 4y^2 - 12y + 9

c) x^2/4 - xy + y^2

d) x^2 - 5x + 25/4

e) 4x^2 + 32xy + 64y^2

f) 9x^2 - 30xy + 25y^2

a,

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

b,

$12x^2y^3z^4+(-7x^2y^3z^4)=12x^2y^3z^4-7x^2y^3z^4=5x^2y^3z^4$

c,

$-6xy^3-(-6xy^3)+6x^3=-6xy^3+6xy^3+6x^3=0+6x^3=6x^3$

d,

$\frac{-x^2}{2}+\frac{7}{2}x^2+x=(\frac{7}{2}-\frac{1}{2})x^2+x$

$=3x^2+x$

e,

$2x^3+3x^3-\frac{1}{3}x^3=(2+3-\frac{1}{3})x^3=\frac{14}{3}x^3$

f,

$5xy^2+\frac{1}{2}xy^2+\frac{1}{4}xy^2=(5+\frac{1}{2}+\frac{1}{4})xy^2$

$=\frac{23}{4}xy^2$

\(a,=4x^2+12xy+9y^2\\ b,=25x^2-10xy+y^2\\ d,=4x^2+4xy^2+y^4\\ e,=9x^4-12x^2y+4y^2\\ g,=x^3+64\)

a: \(=\dfrac{6}{3}\cdot x\cdot\dfrac{y^2}{y}=2xy\)

b: \(=\dfrac{62}{2}\cdot\dfrac{x^4}{x^3}\cdot\dfrac{y^3}{y^2}=31xy\)

c: \(=\dfrac{-18}{6}\cdot\dfrac{x^4}{x^2}\cdot\dfrac{y^3}{y}=-3x^2y^2\)

d: \(=\dfrac{27}{9}\cdot\dfrac{x^5}{x^3}\cdot\dfrac{y^6}{y^3}=3x^2y^3\)

e: \(=\dfrac{18}{12}\cdot\dfrac{x^3}{x}\cdot\dfrac{y^4}{y^3}=\dfrac{3}{2}x^2y\)

a,\(\dfrac{3-x}{x-5}+\dfrac{2x-8}{x-5}=\dfrac{3-x+2x-8}{x-5}=\dfrac{x-5}{x-5}=1\)

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

a: \(\dfrac{4x^4y-7x^2y+3y}{-3x^2+2y}\)

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

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

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

a) `(4x^4y-7x^2y+3y).(2y-3x^2y)`

`=8x^4y^2-14x^2y^2+6y^2-12x^6y^2+21x^4y^2-9x^2y^2`

`=29x^4y^2-12x^6y^2-23x^2y^2+6y^2`

b) `(x^2+3x-3/2 x^3):2x - x/2 . (1-3/2 x)`

`=(x+3-3/2 x^2):2 - (x/2 - 3/4 x^2)`

`=x/2 + 3/2 - 3/4 x^2 -x/2 +3/4 x^2`

`=3/2`

c) `(-2x^3-x-3+5x^2):(3-2x)`

`=(3-2x)(x^2-x-1) : (3-2x)`

`=x^2-x-1`

\(a,=4x^2-4x+1-4x^2+4-x^2-x+6=-x^2-5x+11\\ b,=8x^3+27-8x^3+72x=72x+27\)

a) \(=4x^2-4x+1-4\left(x^2-1\right)-\left(x^2-2x+3x-6\right)=4x^2-4x+1-4x^2+4-x^2-x+6=-x^2-5x+11\)

b) \(=8x^3+27-8x\left(x^2-9\right)=8x^3+27-8x^3+72x=72x+27\)