Question

[Đỗ thị như quỳnh]

Tìm x :

\(\left(2x^2+1\right)\cdot\left(3x^2-1\right)-\left(4x^2-3\right)\cdot\left(x^2+1\right)=x\cdot\left(2x^2+1\right)\)

Answer 1

[Nguyễn Lê Phước Thịnh]

Sửa đề: \(\left(2x^2+1\right)\left(3x^2-1\right)-\left(4x^2-3\right)\left(x^2+1\right)=x^2\left(2x^2+1\right)\)

\(\Leftrightarrow6x^4-2x^2+3x^2-1-\left(4x^4+4x^2-3x^2-3\right)=2x^4+x^2\)

\(\Leftrightarrow6x^4+x^2-1-4x^4-x^2+3-2x^4-x^2=0\)

\(\Leftrightarrow-x^2+2=0\)

hay \(x\in\left\{\sqrt{2};-\sqrt{2}\right\}\)