5x^2 + 5xy - x - y 

=5x.(x+y)-(x+y)

=(x+y)(5x-1)

7x - 6x^2 - 2

=-6x²+3x+4x-2

=-3x.(2x-1)+2.(2x-1)

=(2x-1)(2-3x)

\(y-2x\sqrt{y}-3x\sqrt{y}+6x^2=\sqrt{y}\left(\sqrt{y}-2x\right)-3x\left(\sqrt{y}-2x\right)=\left(\sqrt{y}-3x\right)\left(\sqrt{y}-2x\right)\)

\(=6x^2+5x-3xy\)

\(=x\left(6x+5-3y\right)\)

\(x^2-6x+16\)

\(=x^2+2x-8x-16\)

\(=x^2+2x-\left(8x+16\right)\)

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

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

+16 co ma

Bài này ko thể phân tích theo kiểu lớp 8 được (chưa học căn thức)

\(2x^2-6x+1=\left(\sqrt{2}x\right)^2-2.\sqrt{2}x.\frac{3\sqrt{2}}{2}+\left(\frac{3\sqrt{2}}{2}\right)^2-\frac{7}{2}\)

\(=\left(\sqrt{2}x-\frac{3\sqrt{2}}{2}\right)^2-\left(\frac{\sqrt{14}}{2}\right)^2\)

\(=\left(\sqrt{2}x-\frac{3\sqrt{2}}{2}+\frac{\sqrt{14}}{2}\right)\left(\sqrt{2}x-\frac{3\sqrt{2}}{2}-\frac{\sqrt{14}}{2}\right)\)

\(=\left(\sqrt{2}x+\frac{\sqrt{14}-3\sqrt{2}}{2}\right)\left(\sqrt{2}x-\frac{\sqrt{14}+3\sqrt{2}}{2}\right)\)

\(2x^2-6x+1=2\left(x^2-3x+\frac{9}{4}-\frac{7}{4}\right)=2\left[\left(x-\frac{3}{2}\right)^2-\left(\frac{\sqrt{7}}{2}\right)^2\right]=2\left(x-\frac{3}{2}-\frac{\sqrt{7}}{2}\right)\left(x-\frac{3}{2}+\frac{\sqrt{7}}{2}\right)\)

\(=2\left(x-\frac{3+\sqrt{7}}{2}\right)\left(x-\frac{3-\sqrt{7}}{2}\right)\)

đề có sai ko bn?

\(6x^3+x^2+x+1=\left(6x^3+3x^2\right)+\left(-2x^2-x\right)+\left(2x+1\right)\)

\(=3x^2.\left(2x+1\right)-x.\left(2x+1\right)+\left(2x+1\right)=\left(2x+1\right)\left(3x^2-x+1\right)\)

K sai dau
giao an truong Tran dai nghia do

cái này dễ mà

= (2x)^3-3(2x)^2*1+2*3x*1^2-1^3

= (2x-1)^3