Answer:

\(25x^2-10x+4y-4y^2\)

\(=25x^2-10x+1-4x^2+4y-1\)

\(=\left(25x^2-10x+1\right)-\left(4y^2-2y+1\right)\)

\(=[\left(5x\right)^2-2.5x.1+1]-[\left(2y\right)^2-2.2y.1+1]\)

\(=\left(5x-1\right)^2-\left(2y-1\right)^2\)

\(=\left(5x-1-2y+1\right).\left(5x-1+2y-1\right)\)

\(=\left(5x-2y\right).\left(5x+2y-2\right)\)

\(x^3-10x^2+25x-16xy^2\)

\(=x\left(x^2-10x+25-16y^2\right)\)

\(=x\left[\left(x-5\right)^2-16y^2\right]\)

\(=x\left(x-4y-5\right)\left(x+4y-5\right)\)

p/s: chúc bạn học tốt

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

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

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

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

\(a\sqrt{a}+2a+\sqrt{a}+2=\left(a\sqrt{a}+2a\right)+\left(\sqrt{a}+2\right)\)

\(=a\left(\sqrt{a}+2\right)+\left(\sqrt{a}+2\right)=\left(\sqrt{a}+2\right)\left(a+1\right)\)

\(a\sqrt{a}+2a+\sqrt{a}+2=a\left(\sqrt{a}+2\right)+\left(\sqrt{a}+2\right)=\left(a+1\right)\left(\sqrt{a}+2\right)\)

\(a\sqrt{a}+2a+\sqrt{a}+2=\left(\sqrt{a}+2\right)\left(a+1\right)\)

Câu b đề sai nha bạn.

a) \(x^3+9x^2+27x+27=\left(x+3\right)^3\)

b) \(3\sqrt{3x^3}+18x^2+12\sqrt{3x}+8=\left(\sqrt{3x}+2\right)^3\)

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

\(\left(25x^2-2\right)=\left(5x-\sqrt[]{2}\right)\left(5x+\sqrt[]{2}\right)\)