Question

[Cô nàng Thiên Yết]

Tìm x biết

a) 4x² (x-2) - x +2 = 0

g) x² - 7x + 10 = 0

Answer 1

[KAl(SO4)2·12H2O]

a) \(4x^2\left(x-2\right)-x+2=0\)

\(\Leftrightarrow4x^2\left(x-2\right)-\left(x-2\right)=0\)

\(\Leftrightarrow\left(x-2\right)\left(4x^2-1\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-2=0\\4x^2-1=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=2\\x=\pm\frac{1}{2}\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=2\\x=\pm\frac{1}{2}\end{cases}}\)

g) \(x^2-7x+10=0\)

\(\Leftrightarrow\left(x-5\right)\left(x-2\right)=0\)

\(\Leftrightarrow\orbr{\begin{cases}x-5=0\\x-2=0\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=5\\x=2\end{cases}}\)

\(\Rightarrow\orbr{\begin{cases}x=5\\x=2\end{cases}}\)