Question

a) (a - 2)² = 16

2 TH nhé. Mik giải ra rồi nhưng muốn kt lại thôi/

Answer 1

\(\left(a-2\right)^2=16\)

\(\Leftrightarrow\left(a-2\right)^2=\pm\sqrt{16}\)

\(\Leftrightarrow\left(a-2\right)=\pm4\)

\(\Leftrightarrow\left[\begin{array}{nghiempt}a-2=4\\a-2=-4\end{array}\right.\Leftrightarrow\left[\begin{array}{nghiempt}a=6\\a=-2\end{array}\right.\)

Vậy \(a\in\left\{6;-2\right\}\)