Question

giải phương trình tích sau:
(x² + 5x²) - 2 (x² + 5x) - 24 = 0

Answer 1

\(\left(x^2+5x^2\right)-2\left(x^2+5x\right)-24=0\)

\(\Leftrightarrow4x^2-10x-24=0\)

\(\Leftrightarrow\frac{-\left(-10\right)+\sqrt{\left(-10\right)^2-4.4.\left(-24\right)}}{2.4}\)

\(\Leftrightarrow\frac{10+\sqrt{484}}{2.4}\)

\(\Leftrightarrow\frac{10+\sqrt{484}}{8}\)

\(\Leftrightarrow\frac{-\left(-10\right)-\sqrt{\left(-10\right)^2-4.4.\left(-24\right)}}{2.4}\)

\(\Leftrightarrow\frac{10-\sqrt{\left(10\right)^2+4.4.24}}{2.4}\)

\(\Leftrightarrow\frac{10-\sqrt{484}}{8}\)

\(\Rightarrow\hept{\begin{cases}x=4\\x=-\frac{3}{2}\end{cases}}\)

Sai đâu sửa hộ :)