\(-9x^2+6x+y^2-1\)

\(=-\left(9x^2-6x+1-y^2\right)\)

\(=-\left(3x-1-y\right)\left(3x-1+y\right)\)

\(9x^2-4\left(x-1\right)^2\)

\(=\left[3x+2\left(x-1\right)\right]\left[3x-2\left(x-1\right)\right]\)

\(=\left[3x+2x-2\right]\left[3x-2x+2\right]\)

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

Trí làm đúng rồi nha

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

\(-x^3+9x^2-27x+27\)

\(=-x^3+3x^2+6x^2-18x-9x+27\)

\(=-x^2\left(x-3\right)+6x\left(x-3\right)-9\left(x-3\right)\)

\(=-\left(x-3\right)\left(x^2-6x+9\right)\)

\(=-\left(x-3\right)\left(x-3\right)^2\)

\(=\left(3-x\right)^3\)

       \(x^3-9x^2+14x\)

= \(x^3-7x^2-2x^2+14x\)

= \(x^2.\left(x-7\right)-2x.\left(x-7\right)\)

= \(\left(x-7\right).\left(x^2-2x\right)\)

= \(\left(x-7\right).\left(x-2\right).x\)

\(x^3-9x^2+14x\)

\(=x\left(x^2-9x+14\right)\)

\(=x\left(x^2-7x-2x+14\right)\)

\(=x\left[x\left(x-7\right)-2\left(x-7\right)\right]\)

\(=x\left(x-2\right)\left(x-7\right)\)

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

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

chỉnh lại đề nè:không có chữ chung nhé

Mk mới lớp 7 thui nên mình ko làm đc bài này.

\(=\left(3x-y\right)\left(9x-3y\right)=3\left(3x-y\right)^2\)

=9x(3x-y)-3y(3x-y)
=(3x-y)(9x-3y)
Chúc bạn học tốt nha ^^