Question

Tìm x, biết:

a,x/-15=-60/x

b,-2/x=-x/0.32

Answer 1

a) \(-\frac{x}{15}=-\frac{60}{x}\Rightarrow-15.\left(-60\right)=x^2\Rightarrow900=x^2\Rightarrow x=\sqrt{900}=30\)

\(x=-\sqrt{900}=-30\)

b) \(-\frac{2}{x}=-\frac{x}{0,32}\Rightarrow-2.\left(-0,32\right)=x^2\Rightarrow\frac{16}{25}=x^2\Rightarrow x=\frac{\sqrt{16}}{\sqrt{25}}=\frac{4}{5}\)

\(x=-\frac{\sqrt{16}}{\sqrt{25}}=-\frac{4}{5}\)

Answer 2

a) \(\frac{x}{-15}=\frac{-60}{x}\)

=> x.x = (-60)  .  (-15)

=>x²  = 900

=>x²  = 30²

=>x=30

b)\(\frac{-2}{x}=\frac{-x}{0,32}\)

=>x.(-x) =(-2).0,32

=>-(x²)  =-0,64

=>-(x²)  =-(0,8²)

=>x=0,8