a) x²(5x³ – x - \(\dfrac{1}{2}\) )= x². 5x³ + x² . (-x) + x² . (-\(\dfrac{1}{2}\))

= 5x⁵ – x³ – \(\dfrac{1}{2}\)x²

b) (3xy – x² + y)\(\dfrac{2}{3}\)x²y = \(\dfrac{2}{3}\)x²y . 3xy + \(\dfrac{2}{3}\)x²y . (- x²) + \(\dfrac{2}{3}\)x²y . y

= 2x³y² – \(\dfrac{2}{3}\)x⁴y + \(\dfrac{2}{3}\)x²y²

c) (4x³– 5xy + 2x)(- \(\dfrac{1}{2}\)xy) = - \(\dfrac{1}{2}\)xy . 4x³ + (- \(\dfrac{1}{2}\)xy) . (-5xy) + (- \(\dfrac{1}{2}\)xy) . 2x

= -2x⁴y + \(\dfrac{5}{2}\)x²y² - x²y.

a) x² (5x³ - x - \(\dfrac{1}{2}\))

= 5x⁵ - x³ - \(\dfrac{1}{2}\)x²

b) (3xy - x² + y) \(\dfrac{2}{3}\)x²y

= 2x³y² - \(\dfrac{2}{3}\)x⁴y + \(\dfrac{2}{3}\)x²y²

c) (4x³ - 5xy +2x) (-\(\dfrac{1}{2}\)xy)

= -2x⁴y + \(\dfrac{5}{2}\)x²y² - x²y

a,3x(5x^2-2x-1)

=15x^3-6x^2-3x

a) \(3x\left(5x^2-2x-1\right)\)

\(=15x^3-6x^2-3x\)

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

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

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

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

a) 3x(5x²-2x-1) = 15x³ - 6x² - 3x

b) (x²+2xy-3)(-xy) = -x³y - 2x²y² + 3xy

c) \(\dfrac{1}{2}\)x²y\((\)2x³ - \(\dfrac{2}{5}\)xy² - 1) = x⁵y - \(\dfrac{1}{5}\)x³y³ - \(\dfrac{1}{2}\)x²y

1.

a)\(\left(\dfrac{1}{2}\cdot\left(-2\right)\cdot\dfrac{-1}{3}\right)\cdot\left(x^2\cdot x^2\cdot x^2\right)\cdot\left(y^2\cdot y^3\right)\cdot z\)

\(\dfrac{1}{3}x^6y^5z\)

Deg=12

Mấy câu kia tương tự nha cố gắng lên!

a)\(3x\left(x^2-7x+9\right)\)

\(=3x.x^2-3x.7x+3x.9\)

\(=3x^3-21x^2+27x\)

b)\(\dfrac{2}{5}xy\left(x^2y-5x+10y\right)\)

\(=\dfrac{2}{5}xy.x^2y-\dfrac{2}{5}xy.5x+\dfrac{2}{5}xy.10y\)

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

a)

\(=2x^2.5x^2−2x^2.2x+2x^2−3x.5x^2+3x.2x−3x\)

\(=10x^4−4x^3+2x^2−15x^3+6x^2−3x\)

\(=10x^4−19x^3+8x^2−3x\)

b) \((x−2y)(3xy+5y^2+x)\)

\(=x.3xy+x.5y^2+x.x−2y.3xy−2y.5y^2−2y.x\)

\(=3x^2y+5xy^2+x^2−6xy^2−10y^3−2xy\)

\(=3x^2y−xy^2−2xy+x^2−10y^3\)

a: \(=3y^2-5x^2y^3-2y^2+3x^2y^3=y^2-2x^2y^3\)

b: \(=6x-y+2x^2+3y^2-2x^2+x=7x-y+3y^2\)

c: \(=x-y+4y^2-6xy+\dfrac{10x^2}{y}\)

\(a.\left(9x^2y^3-15x^4y^4\right):3x^2y-\left(2-3x^2y\right)y^2\)

\(=3y^2-5x^2y^3-2y^2+3x^2y^3\)

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

\(b.\left(6x^2-xy\right):x+\left(2x^3y+3xy^2\right):xy-\left(2x-1\right)x\)

\(=6x-y+2x^2+3y-2+x\)

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

\(c.\left(x^2-xy\right):x+\left(6x^2y^5-9x^3y^4+15x^4y^3\right):\dfrac{3}{2}x^2y^3\)

\(=x-y+4y^2-6xy+10x^2\)

Bài giải:

a) (-2x⁵ + 3x² – 4x³) : 2x² = (- $\frac{2}{2}$)x^{5 – 2} + $\frac{3}{2}$x^{2 – 2} + (-$\frac{4}{2}$)x^{3 – 2} = - x³ + $\frac{3}{2}$ – 2x.

b) (x³ – 2x²y + 3xy²) : (- $\frac{1}{2}$x) = (x³ : -$\frac{1}{2}$x) + (-2x²y : -$\frac{1}{2}$x) + (3xy² : -$\frac{1}{2}$x)

= -2x² + 4xy – 6y²

c)(3x²y² + 6x²y³ – 12xy) : 3xy = (3x²y² : 3xy) + (6x²y² : 3xy) + (-12xy : 3xy)

= xy + 2xy² – 4.

a) (-2x⁵+3x²-4x³) : 2x²

= (-2x⁵:2x²)-(4x³:2x²)+(3x²:2x²)

= -x³-2x+\(\dfrac{3}{2}\)

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

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

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

c) \(\left(3x^2y^2+6x^2y^3-12xy\right):3xy\)

= \(\left(6x^2y^3:3xy\right)+\left(3x^2y^2:3xy\right)+\left(-12xy:3xy\right)\)

= \(xy^2+xy-4\)