Question

Tìm x biết: 3x² + 5,2 = 32,2

Answer 1

\(3x^2+5,2=32,2\Leftrightarrow3x^2=27\Leftrightarrow x^2=9\Leftrightarrow\left[\begin{array}{nghiempt}x=3\\x=-3\end{array}\right.\)

Answer 2

3x² + 5,2 = 32,2

3x² = 32,2 - 5,2

3x² = 27

x² = 27 : 3

x² = 9

x = 3 hoặc x = - 3

Answer 3

3x² + 5,2 = 32,2

3x² = 32,2 - 5,2

3x² = 27

x² = 27 : 3

x² = 9

\(\Rightarrow\) \(\begin{cases}x=\sqrt{9}\\x=-\sqrt{9}\end{cases}\) \(\Rightarrow\) \(\begin{cases}3\\-3\end{cases}\)