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) \(\left(4x^3-5xy+2x\right)\left(-\dfrac{1}{2}xy\right)\)
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Những câu hỏi liên quan
1 tháng 5 2017
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
24 tháng 5 2022
a: \(=\dfrac{1}{x-y}-\dfrac{3xy}{\left(x-y\right)\left(x^2+xy+y^2\right)}+\dfrac{x-y}{x^2+xy+y^2}\)
\(=\dfrac{x^2+xy+y^2-3xy+x^2-2xy+y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}\)
\(=\dfrac{2x^2-4xy+2y^2}{\left(x-y\right)\left(x^2+xy+y^2\right)}=\dfrac{2\left(x-y\right)}{x^2+xy+y^2}\)
d: \(=\dfrac{x^3-1}{x-1}-\dfrac{x^2-1}{x+1}\)
\(=x^2+x+1-x+1=x^2+2\)
19 tháng 7 2022
a: \(=6x^4-9x^3+3x^2-4x^3+6x^2-2x+10x^2-15x+5\)
\(=6x^4-13x^3+19x^2-17x+5\)
b: \(=6x^4-\dfrac{9}{4}x^3-\dfrac{9}{2}x^2-\dfrac{8}{3}x^3+x^2+2x-\dfrac{20}{3}x^2+\dfrac{5}{2}x+5\)
\(=6x^4-\dfrac{59}{12}x^3-\dfrac{67}{6}x^2+\dfrac{9}{2}x+5\)
c: \(=3x^4-\dfrac{9}{8}x^3-\dfrac{3}{4}x^2+8x^3-3x^2-6x-\dfrac{4}{3}x^2+\dfrac{1}{2}x+1\)
\(=3x^4-\dfrac{55}{8}x^3-\dfrac{25}{12}x^2-\dfrac{11}{2}x+1\)
13 tháng 6 2022
a: \(=\dfrac{4x^2+4x+1-\left(4x^2-4x+1\right)}{\left(2x-1\right)\left(2x+1\right)}\cdot\dfrac{5\left(2x-1\right)}{4x}\)
\(=\dfrac{8x}{2x+1}\cdot\dfrac{5}{4x}=\dfrac{10}{2x+1}\)
c: \(=\dfrac{1}{x-1}-\dfrac{x\left(x-1\right)\left(x+1\right)}{x^2+1}\cdot\left(\dfrac{x+1-x+1}{\left(x-1\right)^2\cdot\left(x+1\right)}\right)\)
\(=\dfrac{1}{x-1}-\dfrac{x}{x^2+1}\cdot\dfrac{2}{\left(x-1\right)}=\dfrac{x^2+1-2x}{\left(x-1\right)\left(x^2+1\right)}=\dfrac{x-1}{x^2+1}\)
PT
11 tháng 12 2017
a) \(\left(\dfrac{2x+1}{2x-1}-\dfrac{2x-1}{2x+1}\right):\dfrac{4x}{10x-5}\)
\(=\left(\dfrac{\left(2x+1\right)\left(2x+1\right)}{2x^2-1}-\dfrac{\left(2x-1\right)\left(2x-1\right)}{2x^2-1}\right):\dfrac{4x}{10x-5}\)
\(=\left(\dfrac{\left(2x+1\right)^2-\left(2x-1\right)^2}{2x^2-1}\right):\dfrac{4x}{10x-5}\)
\(=\left(\dfrac{\left(2x+1-2x-1\right)\left(2x+1+2x-1\right)}{2x^2-1}\right):\dfrac{4x}{10x-5}\)
\(=\dfrac{4x}{2x^2-1}.\dfrac{5\left(2x-1\right)}{4x}\)
\(=\dfrac{5}{2x+1}\)
b) \(\left(\dfrac{1}{x^2+1}-\dfrac{2-x}{x+1}\right):\left(\dfrac{1}{x}+x-2\right)\)
\(=\left(\dfrac{1}{x^2+1}-\dfrac{x\left(2-x\right)}{x\left(x+1\right)}\right):\left(\dfrac{1}{x}+x-2\right)\)
\(=\left(\dfrac{1-2x+x^2}{x^2+1}\right):\left(\dfrac{1}{x}+x-2\right)\)
\(=\left(\dfrac{1-2x+x^2}{x^2+1}\right):\left(\dfrac{1}{x}+\dfrac{x^2}{x}-\dfrac{2x}{x}\right)\)
\(=\left(\dfrac{1-2x+x^2}{x^2+1}\right):\left(\dfrac{x^2-2x+1}{x}\right)\)
\(=\dfrac{\left(x-1\right)^2}{x^2+1}.\dfrac{x}{\left(x-1\right)^2}\)
\(=\dfrac{x}{x^2+1}\)
c) d) Tự làm đi mình làm biếng quass >.< ^^
7 tháng 10 2021
a: \(5x^2y^4:10x^2y=\dfrac{1}{2}y^3\)
c: \(\left(-xy\right)^{10}:\left(-xy\right)^5=-x^5y^5\)
17 tháng 10 2017
Bài 45: (SBT/12):
a. (5x4 - 3x3 + x2) : 3x2
= (5x4 : 3x2) + (-3x3 : 3x2) + (x2 : 3x2)
=\(\dfrac{5}{2}\)x2 - x + \(\dfrac{1}{3}\)
b. (5xy2 + 9xy - x2y2) : (-xy)
= [5xy2 : (-xy)] + [9xy : (-xy)] + [(-x2y2) : (-xy)]
= -5y - 9 + xy
c. (x3y3 : \(\dfrac{1}{3}\)x2y3 - x3y2) : \(\dfrac{1}{3}\)x2y2
= (x3y3 : \(\dfrac{1}{3}\)x2y2) + (-\(\dfrac{1}{2}\)x2y3 : \(\dfrac{1}{3}\)x2y2) + (-x3y2 : \(\dfrac{1}{3}\)x2y2)
= 3xy - \(\dfrac{3}{2}\)y - 3x
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