1: \(x-9=\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)\)

2: \(x-16=\left(\sqrt{x}-4\right)\left(\sqrt{x}+4\right)\)

3: \(9x-1=\left(3\sqrt{x}-1\right)\left(3\sqrt{x}+1\right)\)

4: \(x\sqrt{x}+1=\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)\)

\(1,x-9=\left(\sqrt{x}-3\right)\left(\sqrt{x}+3\right)\\ 2,x-16=\left(\sqrt{x}-4\right)\left(\sqrt{x}+4\right)\\ 3,9x-1=\left(3\sqrt{x}-1\right)\left(3\sqrt{x}+1\right)\\ 4,x\sqrt{x}+1=\left(\sqrt{x}+1\right)\left(x-\sqrt{x}+1\right)\)

 1,x−9=(√x−3)(√x+3)

2,x−16=(√x−4)(√x+4)

3,9x−1=(3√x−1)(3√x+1)

4,x√x+1=(√x+1)(x−√x+1

\(9\left(x+5\right)^2-\left(x-7\right)^2\)

\(=\left(3x+15\right)^2-\left(x-7\right)^2\)

\(=\left(3x+15-x+7\right)\left(3x+15+x-7\right)\)

\(=\left(2x+22\right)\left(4x+8\right)\)

\(=2\left(x+11\right).4\left(x+2\right)\)

\(=8\left(x+11\right)\left(x+2\right)\)

\(16-x^2\)

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

\(---\)

\(16-3x+1^2\) (kt lại đề bài nhé)

\(x^4y^4+4x^2y^2+4\)

\(=\left[\left(xy\right)^2\right]^2+2\cdot\left(xy\right)^2\cdot2+2^2\)

\(=\left[\left(xy\right)^2+2\right]^2=\left(x^2y^2+2\right)^2\)

\(---\)

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

\(=y^2-2\cdot y\cdot2+2^2-x^2\)

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

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

\(\left(x+2\right)^2-16\\ \backslash=\left(x+2-4\right)\left(x+2+4\right)\\ =\left(x-2\right)\left(x+6\right)\)

(x+2)²-4²=(x+2-4)(x+2+4)

 ( x + 2) ² - 16

= (x+2)² -  4²

= (x+2-4) . (x+2+4)

= (x -2) . (x+6) 

\(x^2\left(x-1\right)+16\left(1-x\right)\)

\(=x^2\left(x-1\right)-16\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2-4^2\right)\)

\(=\left(x-1\right)\left(x-4\right)\left(x-4\right)\)

=x²(x-1)-16(x-1)

=(x-1) (x²-16)

=(x-1)(x-4)(x+4)

\(x^2\left(x-1\right)+16\left(1-x\right)\)

\(=x^2\left(x-1\right)-16\left(x-1\right)\)

\(=\left(x-1\right)\left(x^2-4^2\right)\)

\(=\left(x-1\right)\left(x-4\right)\left(x-4\right)\)

\(\left(x+3\right)^2-16\)

\(=\left(x+3-4\right)\left(x+3+4\right)\)

\(=\left(x-1\right)\left(x+7\right)\)

1: =(16x^2-8x+1)-y^2

=(4x-1)^2-y^2

=(4x-1-y)(4x-1+y)

2: =(x^2-2xy+y^2)-z^2

=(x-y)^2-z^2

=(x-y-z)(x-y+z)

3: =(x^2+4xy+4y^2)-16

=(x+2y)^2-4^2

=(x+2y-4)(x+2y+4)

4: =(x^2-4xy+4y^2)-16

=(x-2y)^2-4^2

=(x-2y-4)(x-2y+4)

a) \(x^2-xy+x-y\)

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

\(=\left(x+1\right)\left(x-y\right)\)

b) \(x^2+5x+6\)

\(=x^2+2x+3x+6\)

\(=x\left(x+2\right)+3\left(x+2\right)\)

\(=\left(x+3\right)\left(x+2\right)\)

\(2xy-x^2-y^2+16\)

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

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