Question

2x²-1=49

Answer 1

\(2x^2-1=49\)

        \(2x^2=49+1\)

        \(2x^2=50\)

          \(x^2=50:2\)

          \(x^2=25\)

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

Answer 2

\(2x^2-1=49\)

\(\Leftrightarrow2x^2=50\)

\(\Leftrightarrow x^2=50:2\)

\(\Leftrightarrow x^2=25\)

\(\Leftrightarrow x=\sqrt{25}\)

\(\Rightarrow x=5\)

Vậy \(x=5\)

Answer 3

Nhầm tí \(\sqrt{25}=5;-5\)

Answer 4

2x² - 1 = 49

<=>2x²      = 49 + 1

<=> 2x²      = 50

<=>   x²      = 50 : 2

<=>   x²        = 25

<=>   x²      = 5²

 =>    x        = 5

Answer 5

5 hoặc -5

Answer 6

2x^2=49+1

2x^2=50

x^2=50

=>x=5

Answer 7

\(2x^2-1=49\)

\(2x^2=49+1\)

\(2x^2=50\)

\(x^2=50\div2\)

\(x^2=25\)

\(\Rightarrow x\in\){5 ; -5}