a) (a - 2)2 = 16
2 TH nhé. Mik giải ra rồi nhưng muốn kt lại thôi/
a) (a - 2)2 = 16
2 TH nhé. Mik giải ra rồi nhưng muốn kt lại thôi/
\(\left(a-2\right)^2=16\)
\(\Leftrightarrow\left(a-2\right)^2=\pm\sqrt{16}\)
\(\Leftrightarrow\left(a-2\right)=\pm4\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}a-2=4\\a-2=-4\end{array}\right.\Leftrightarrow\left[\begin{array}{nghiempt}a=6\\a=-2\end{array}\right.\)
Vậy \(a\in\left\{6;-2\right\}\)
Tìm x \(\in\) Q
a) \(\frac{-2}{x}\) =\(\frac{x}{\frac{8}{25}}\) b)0,01:2,5=(0,75x):0,75
a ) \(\frac{-2}{x}=\frac{x}{\frac{8}{25}}\)
\(\Leftrightarrow x^2=-2.-\frac{16}{25}\)
\(\Leftrightarrow x^2=\frac{16}{25}\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\sqrt{\frac{16}{25}}\\x=-\sqrt{\frac{16}{25}}\end{array}\right.\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{4}{5}\\x=-\frac{4}{5}\end{array}\right.\)
Vậy ......................................