(2\(x^2\)).(\(x^3\) - \(x\)) - 2\(x^2\).(\(x^3\) - \(x+1\))- (2\(x\) - 5\(x^2\))\(x\)

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

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

= 0 - (0 + 5\(x^3\)) - 4\(x^2\)

= - 5\(x^3\) - 4\(x^2\)

x(2x²-3)-x²(5x+1)+x²

=2x³-3x-5x³-x²+x²

=-3x³-3x

cảm ơn                

4x.(6x²- 4x-3x+2)-5x.(x-2)(x-2)

----------------------- -5x. (x²-2x-2x+4)

bn làm nốt nhé

từ đề:

\(=\left(8x^2-4x\right)\left(3x-2\right)-5x\left(x^2-4x+4\right)\)

\(=24x^3-16x^2-12x^2+8x-5x^3+20x^2-20x\)

\(=19x^3-8x^2-12x\)

a, \(ĐKXĐ:x\ne\pm\frac{1}{5},x\ne\frac{3}{2}\)

\(\Rightarrow P=\frac{\left(5x+1\right)\left(x+2\right)}{\left(2x-3\right)\left(5x-1\right)\left(5x+1\right)}-\frac{\left(8-3x\right)\left(5x+1\right)}{\left(5x-1\right)\left(5x+1\right)\left(2x-3\right)}\)

\(=\frac{x+2}{\left(2x-3\right)\left(5x-1\right)}-\frac{8-3x}{\left(5x-1\right)\left(2x-3\right)}\)

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

b, Để P có giá trị nguyên thì  \(2⋮5x-1\)

\(\Rightarrow5x-1\in\left\{1,2,-1,-2\right\}\)

=> x=..............

ĐKXĐ : x \(\ne\frac{3}{2}\) ; \(x\ne\frac{1}{5};x\ne-\frac{1}{5}\) 

P= \(\frac{5x+1}{2x-3}.\left(\frac{x+2}{25x^2-1}-\frac{8-3x}{25x^2-1}\right)\) 

P= \(\frac{5x-1}{2x-3}.\left(\frac{4x-6}{\left(5x+1\right).\left(5x-1\right)}\right)\)

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

P= \(\frac{2}{5x-1}\) 

KL

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

b, \(\frac{2x^2+2x}{x+1}=\frac{2x\left(x+1\right)}{x+1}=2x\)

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

\(b,\frac{2x^2+2x}{x+1}=\frac{2x\left(x+1\right)}{x+1}=2x\)

1) \(x\left(x+4\right)\left(x-4\right)-\left(x^2+1\right)\left(x^2-1\right)\)

\(=x\left(x^2-16\right)\)

\(=x^3-16x-\left(x^2+1\right)\left(x^2-1\right)\)

\(=x^3-16x-x^4+1\)

b) \(7x\left(4y-x\right)+4y\left(y-7x\right)-2\left(2y^2-3.5x\right)\)

\(=28xy-7x^2+4y\left(y-7x\right)-2\left(2y^2-3.5x\right)\)

\(=28xy-7x^2+4y^2-28xy-4y^2+7x\)

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

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

\(=6x^2-17x+5-4\left(2x^2-5x+2\right)\)

\(=6x^2-17x+5-8x^2+20x-8\)

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

a)  x(x+4)(x-4)-(x²+1)(x²-1)

=>x(x²-4²)-(x⁴-1²)

=>x³-16x-x⁴+1

=>-x⁴-x³-15x

b)  7x(4y-x)+4y(y-7x)-2(2y²-3.5x)

=>28xy-7x²+4y²-28xy-4y²+30x

=>-7x²+30x

c)  (3x+1)(2x-5)-4(2x²-5x+2)

=>6x²-15x+2x-5-8x²+20x-8

=>-2x²+7x-13

khó quá tui ko biết làm..

k cho tui nha

thanks