a: =2x^5-15x^3-x^2-2x^5-x^3=-16x^3-x^2

b: =x^3+3x^2-2x-3x^2-9x+6

=x^3-11x+6

c: \(=\dfrac{4x^3+2x^2-6x^2-3x-2x-1+5}{2x+1}\)

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

a) \(6x^3\left(\dfrac{1}{3}x^2-\dfrac{5}{2}-\dfrac{1}{6}\right)-2x^5-x^3\)

\(=6x^3\left(\dfrac{1}{3}x^2-\dfrac{16}{6}\right)-2x^5-x^3\)

\(=2x^5-16x^3-2x^5-x^3\)

\(=-17x^3\)

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

\(=x^3+3x^2-2x+3x^2+9x-6\)

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

c) \(\left(4x^3-4x^2-5x+4\right):\left(2x+1\right)\)

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

\(=4x^3-2x^2-7x+\dfrac{2}{x}+\dfrac{3}{2}\)

\(\frac{3x^4-8x^3-10x^2+8x-5}{3x^2-2x+1}\)

\(=\frac{x^2\left(3x^2-2x+1\right)-2x\left(3x^2-2x+1\right)-5\left(3x^2-2x+1\right)}{3x^2-2x+1}\)

\(=\frac{\left(3x^2-2x+1\right)\cdot\left(x^2-2x-5\right)}{3x^2-2x+1}\)

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

\(\frac{2x^3-9x^2+19x-15}{x^2-3x+5}\)

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

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

\(=2x-3\)

\(\frac{\left(8x^3-y^3\right)\left(4x^2-y^2\right)}{\left(2x+y\right)\left(4x^2-4xy+y^2\right)}\)

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

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

bài tập tết nâng cao phải ko

mk cũng có nhưng chưa làm dc

len google di ban

mk chua hoc bai nay

a, \(\dfrac{x^2+y^2}{4\left(x+y\right)}+\dfrac{2xy}{4\left(x+y\right)}\)=\(\dfrac{x^2+2xy+y^2}{4\left(x+y\right)}\)   = \(\dfrac{\left(x+y\right)^2}{4\left(x+y\right)}\)  =\(\dfrac{x+y}{4}\) 

a. \(\dfrac{x^2+y^2}{4\left(x+y\right)}+\dfrac{2xy}{4\left(x+y\right)}\)

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

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

\(=\dfrac{x+y}{4}\)

b. \(\dfrac{x+5}{2x-2}-\dfrac{4}{x^2-1}:\dfrac{2}{x+1}\)

\(=\dfrac{x+5}{2\left(x-1\right)}-\dfrac{4}{\left(x+1\right)\left(x-1\right)}:\dfrac{2}{x+1}\)

\(=\dfrac{x+5}{2\left(x-1\right)}-\dfrac{2}{x-1}\)

\(=\dfrac{x+5}{2\left(x-1\right)}-\dfrac{4}{2\left(x-1\right)}\)

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

a) Ta có: \(\dfrac{x^2+y^2}{4\left(x+y\right)}+\dfrac{2xy}{4\left(x+y\right)}\)

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

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

\(=\dfrac{x+y}{4}\)

b) Ta có: \(\dfrac{x+5}{2x-2}-\dfrac{4}{x^2-1}:\dfrac{2}{x+1}\)

\(=\dfrac{x+5}{2\left(x-1\right)}-\dfrac{4}{\left(x-1\right)\left(x+1\right)}\cdot\dfrac{x+1}{2}\)

\(=\dfrac{x+5}{2\left(x-1\right)}-\dfrac{2}{x-1}\)

\(=\dfrac{x+5}{2\left(x-1\right)}-\dfrac{4}{2\left(x-1\right)}\)

\(=\dfrac{x+5-4}{2\left(x-1\right)}\)

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

a: \(=-2x^2\cdot3x+2x^2\cdot4X^3-2x^2\cdot7+2x^2\cdot x^2\)

\(=8x^5+2x^4-6x^3-14x^2\)

b: \(=2x^3-3x^2-5x+6x^2-9x-15\)

\(=2x^3+3x^2-14x-15\)

c: \(=\dfrac{-6x^5}{3x^3}+\dfrac{7x^4}{3x^3}-\dfrac{6x^3}{3x^3}=-2x^2+\dfrac{7}{3}x-2\)

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

e: \(=\dfrac{2x^4-8x^3-6x^2-5x^3+20x^2+15x+x^2-4x-3}{x^2-4x-3}\)

=2x^2-5x+1

a: \(=\dfrac{x^4-6x^3+12x^2-14x+3}{x^2-4x+1}\)

\(=\dfrac{x^4-4x^3+x^2-2x^3+8x^2-2x+3x^2-12x+3}{x^2-4x+1}\)

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

b: \(=\dfrac{x^5-3x^4+5x^3-x^2+3x-5}{x^2-3x+5}=x^2-1\)

c: \(=\dfrac{2x^4-5x^3+2x^2+2x-1}{x^2-x-1}\)

\(=\dfrac{2x^4-2x^3-2x^2-3x^3+3x^2+3x+x^2-x-1}{x^2-x-1}\)

\(=2x^2-3x+1\)

P/s : Phá ngoặc ra là ok : 

a ) 

\(\left[4x-2\left(x-3\right)\right].\left(-3x\right)\)

\(=\left[4x-2x+6\right]\left(-3x\right)\)

\(=-12x^2+6x^2-18x\)

b ) 

\(3\left[x-3\left(4-2x\right)+8\right]\)

\(=3\left[x-12+6x+8\right]\)

\(=3\left[7x-4\right]\)

\(=21x-12\)

c ) 

\(5\left(3x^2-4y^3\right)+9\left(2x^2-y^3\right)\)

\(=15x^2-20y^3+18x^2-9y^3\)

\(=33x^2-29y^3\)

d ) 

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

\(=6x^2y-3x^2-10x^2y+6x^2\)

\(=-4x^2y+3x^2\)

A= 3x² y-11x²-5y.8xy-5+6

=(3-11-5.8-5+6).(x².x².x).(y.y.y)

=-47x⁵y³