Question

Tìm x, biết:\(\frac{x+2}{0,8}=\frac{0,2}{x+2}\)

Answer 1

\(\frac{x+2}{0,8}=\frac{0,2}{x+2}\)

=> \(\left(x+2\right)^2=0,2\cdot0,8\)

=> \(\left(x+2\right)^2=0,16\)

=> \(x+2=0,4\)       và          \(x+2=-0,4\)

=>  \(x=0,4-2=-1,6\) và  \(x=-0,4-2=-2,4\)

Answer 2

\(\frac{x+2}{0,8}=\frac{0,2}{x+2}\Leftrightarrow\left(x+2\right)\left(x+2\right)=0,2.0,8\Leftrightarrow\left(x+2\right).\left(x+2\right)=0,16\)

\(\Leftrightarrow\left(x+2\right)^2=0,16\)

(+) x + 2 =\(\sqrt{0,16}\) => x + 2 = 0,4 => x = 0,4 - 2 = - 1 ,6

(+) x + 2 = - căn 0,16 =>  x + 2 = - 0,4 => x = -0,4 - 2 = -2,4