a, \(25\left(x-2\right)^2-100\left(y-3\right)^2\)
\(=\left(5x-10\right)^2-\left(10y-30\right)^2\)
\(=\left(5x-10-10y+30\right)\left(5x-10+10y-30\right)\)
\(=\left(5x-10y+20\right)\left(5x+10y-40\right)\)
\(=25\left(x-2y+4\right)\left(x+2y-8\right)\)
b, \(4\left(x+3\right)^2-9\left(x+2\right)^2\)
\(=\left(2x+6\right)^2-\left(3x+6\right)^2\)
\(=\left(2x+6-3x-6\right)\left(2x+6+3x+6\right)\)
\(=-x\left(5x+12\right)\)
c, \(x^2-10x-y^2+25\)
\(=\left(x-5\right)^2-y^2\)
\(=\left(x-y-5\right)\left(x+y-5\right)\)
d, \(x^2-4x-y^2+4\)
\(=\left(x-2\right)^2-y^2\)
\(=\left(x-y-2\right)\left(x+y-2\right)\)
e, \(\left(x^2+2\right)^2-2\left(x^2+2\right)+1\)
\(=\left(x^2+2-1\right)^2\)
\(=\left(x^2+1\right)^2\)
