Question

tim x biet 16-5x^2-3=0

Answer 1

\(16-5x^2-3=0\)

\(\Leftrightarrow16-5x^2=0+3\)

\(\Leftrightarrow16-5x^2=3\)

\(\Leftrightarrow5x^2=16-3\)

\(\Leftrightarrow5x^2=13\)

\(\Leftrightarrow x^2=\frac{13}{5}\)

\(\Leftrightarrow x^2=2,6\)

\(\Leftrightarrow1,61\approx1,6\)

 \(\Rightarrow x=1,6\)

Answer 2

\(16-5x^2-3=0\)

\(\Leftrightarrow16-5x^2=3\)

\(\Leftrightarrow5x^2=16-3\)

\(\Leftrightarrow5x^2=13\Leftrightarrow x^2=\frac{13}{5}\)

\(\Rightarrow\orbr{\begin{cases}x=\sqrt{\frac{13}{5}}\\x=-\sqrt{\frac{13}{5}}\end{cases}}\Leftrightarrow\orbr{\begin{cases}x=\frac{\sqrt{65}}{5}\\x=-\frac{\sqrt{65}}{5}\end{cases}}\)

Answer 3

\(16-5x^2-3=0\)

\(5x^2=16-3\)

\(5x^2=13\)

\(x^2=13:5\)

\(x^2=\frac{13}{5}\)

\(x=\sqrt{\frac{13}{5}}\)

\(x=\frac{\sqrt{65}}{5}\approx1,6\)