Bài 5:
a: \(6x^3-9x^2=3x^2\cdot2x-3x^2\cdot3=3x^2\cdot\left(2x-3\right)\)
b: \(4x^2y-8xy^2+24x^2y^2\)
\(=4xy\cdot x-4xy\cdot2y+4xy\cdot6xy\)
=4xy(x-2y+6xy)
c: \(x^3-x^4=x^3\left(1-x\right)\)
d: \(-8x^4y^3-12x^2y^4+20x^3y^4\)
\(=-4x^2y^3\cdot2x^2-4x^2y^3\cdot3y+4x^2y^3\cdot5xy\)
\(=-4x^2y^3\left(2x^2+3y-5xy\right)\)
Bài 4:
2x(x-3)-5(3-x)=0
=>2x(x-3)+5(x-3)=0
=>(x-3)(2x+5)=0
=>\(\left[\begin{array}{l}x-3=0\\ 2x+5=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=3\\ x=-\frac52\end{array}\right.\)
Bài 3:
1: \(15,8\cdot35+15,8\cdot65\)
\(=15,8\cdot\left(35+65\right)\)
\(=15,8\cdot100=1580\)
2: x(x-1)+y(1-x)
=x(x-1)-y(x-1)
=(x-1)(x-y)
=(2001-1)(2001-501)
=2000*1500
=3000000
