Câu 3:
a: \(\left(10x^3y-5x^2y^2-25x^4y^3\right):\left(-5xy\right)\)
\(=-\frac{10x^3y}{5xy}+\frac{5x^2y^2}{5xy}+\frac{25x^4y^3}{5xy}\)
\(=-2x^2+xy+5x^3y^2\)
Câu 2:
a: \(5x\left(x^2-9\right)=0\)
=>x(x-3)(x+3)=0
=>x∈{0;3;-3}
b: \(3\left(x+3\right)-x^2-3x=0\)
=>3(x+3)-x(x+3)=0
=>(x+3)(3-x)=0
=>\(\left[\begin{array}{l}x+3=0\\ 3-x=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=-3\\ x=3\end{array}\right.\)
c: \(x^2-25=3x-15\)
=>(x-5)(x+5)-3(x-5)=0
=>(x-5)(x+2)=0
=>\(\left[\begin{array}{l}x-5=0\\ x+2=0\end{array}\right.\Rightarrow\left[\begin{array}{l}x=5\\ x=-2\end{array}\right.\)
Câu 1:
a: \(2x^2y-6xy^2=2xy\cdot x-2xy\cdot3y=2xy\left(x-3y\right)\)
b: \(\left(x^2+1\right)^2-4x^2\)
\(=\left(x^2-2x+1\right)\left(x^2+2x+1\right)\)
\(=\left(x-1\right)^2\cdot\left(x+1\right)^2\)
c: \(x^2-10x-9y^2+25\)
\(=\left(x^2-10x+25\right)-9y^2\)
\(=\left(x-5\right)^2-\left(3y\right)^2\)
=(x-5-3y)(x-5+3y)
