\(\Delta=27^2-4.168=57>0\)

pt có 2 nghiệm pb 

\(x=\dfrac{27\pm\sqrt{57}}{2}\)

phân tích thành đa nhân tử mà tú

đâu phải giải pt đâu

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

=x^3(x+1)+x+1

=(x+1)(x^3+1)

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

cảm ơn rất nhiều ạ 

\(x^8-1=\left(x^2-1\right)\left(x^4+x^2+1\right)\)

CÂU SAU THÌ MK KO BIẾT

i) \(=x\left(x-5\right)+3\left(x-5\right)=\left(x-5\right)\left(x+3\right)\)

j) \(=x\left(x-1\right)+8\left(x-1\right)=\left(x-1\right)\left(x+8\right)\)

k) \(=x\left(x+1\right)+3\left(x+1\right)=\left(x+1\right)\left(x+3\right)\)

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

m) \(=x\left(x^2-4x+4\right)=x\left(x-2\right)^2\)

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

3: \(=\sqrt{\left(\sqrt{5}-\sqrt{3}\right)^2}=\sqrt{5}-\sqrt{3}\)

4: \(=\sqrt{\left(\sqrt{5}+\sqrt{3}\right)^2}=\sqrt{5}+\sqrt{3}\)

4x^2 - 7x -2 = 4x^2 - 8x + x - 2 = 4x(x - 2) + (x - 2) = (x -2)(4x + 1)

\(4x^2-7x-2=4x^2-8x+x-2=4x\left(x-2\right)+\left(x-2\right)=\left(x-2\right)\left(4x+1\right)\)