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

\(=10x^4-4x^3+2x^2-15x^3+6x^2-3x\)

\(=10x^4-19x^3+8x^2-3x\)

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

\(=x^3+1-x\left(x^2+8x+15\right)\)

\(=x^3+1-x^3-8x^2-15x\)

\(=-8x^2-15x+1\)

a) Đề:............

= 6x⁴ - 15x³ - 12x²

b) Đề:...........

= x² + 2x + 1 + x² + 3x - 2x - 6 - 4x

= 2x² - x - 5

a: \(=\dfrac{4x-8+2x+4-8}{\left(x-2\right)\left(x+2\right)}=\dfrac{6x-12}{\left(x-2\right)\left(x+2\right)}=\dfrac{6}{x+2}\)

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

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

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

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

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

d: \(=\dfrac{5}{2x-3}+\dfrac{2}{2x+3}+\dfrac{2x-33}{4x^2-99}\)

\(=\dfrac{10x+15+4x-6+2x-33}{\left(2x-3\right)\left(2x+3\right)}=\dfrac{16x-24}{\left(2x-3\right)\left(2x+3\right)}=\dfrac{8}{2x+3}\)

a,\(2xy.3x.2y^3=\left(2.3.2\right)\left(xx\right)\left(yy^3\right)=12x^2y^4\)

b, \(x\left(x^2-2x+5\right)=x^3-2x^2+5x\)

c, \(\frac{3x^2-6x}{3x}=x-2\)

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