Question

Làm tính nhân :

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

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

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

Answer 1

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.

Answer 2

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

Answer 3

Answer 4

x^{2 (} 5x³- x - \(\dfrac{1}{2}\) )

=5x⁵-x³-\(\dfrac{1}{2}\)x²

⁽ 3xy -x² + y) . \(\dfrac{2}{3}\)x²y

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

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

= -2x⁴y + \(\dfrac{5}{2}\)x²y² - x²y

Answer 5

a, = 5x⁵ - x³ - 2/3x⁴y + 2x²y² - x²y

Answer 6

a) x²(5x³ – x - 12 )= x². 5x³ + x² . (-x) + x² . (-12)

= 5x⁵ – x³ – 12x²

b) (3xy – x² + y)23x²y = 23x²y . 3xy + 23x²y . (- x²) + 23x²y . y

= 2x³y² – 23x⁴y + 23x²y²

c) (4x³– 5xy + 2x)(- 12xy) = - 12xy . 4x³ + (- 12xy) . (-5xy) + (- 12xy) . 2x

= -2x⁴y + 52x²y² - x²y.

a) x²(5x³ – x - 12 )= x². 5x³ + x² . (-x) + x² . (-12)

= 5x⁵ – x³ – 12x²

b) (3xy – x² + y)23x²y = 23x²y . 3xy + 23x²y . (- x²) + 23x²y . y

= 2x³y² – 23x⁴y + 23x²y²

c) (4x³– 5xy + 2x)(- 12xy) = - 12xy . 4x³ + (- 12xy) . (-5xy) + (- 12xy) . 2x

= -2x⁴y + 52x²y² - x²y.

Answer 7

a) x2(5x3 – x - 1 2 )= x2. 5x3 + x2 . (-x) + x2 . (- 1 2 ) = 5x5 – x3 – 1 2 x2 b) (3xy – x2 + y) 2 3 x2y = 2 3 x2y . 3xy + 2 3 x2y . (- x2) + 2 3 x2y . y = 2x3y2 – 2 3 x4y + 2 3 x2y2 c) (4x3– 5xy + 2x)(- 1 2 xy) = - 1 2 xy . 4x3 + (- 1 2 xy) . (-5xy) + (- 1 2 xy) . 2x = -2x4y + 5 2 x2y2 - x2y.

Answer 8

8²

Answer 9

a) x²(5x³ – x - 1212)

= 5x⁵ – x³ – 2323x²y = 2323x²y . (- x²) + 2323x⁴y + 1212xy) = - 1212xy) . (-5xy) + (- 5252x²y² - x²y.

_chúc bn lm bt tốt nha_

 

Answer 10

ĐÉO NÓI