Question

Cho b²=ac.Chứng minh rằng 

a²+b²/ b²+c²=a/c

 

Answer 1

xét vế trái ta có:

a^2+b^2/b^2+c^2

=a^2+ac/ac+c^2

=>a.(a+c)/c.(c+a)=a/c

Answer 2

\(bb=ac\)

\(\Rightarrow\frac{b}{c}=\frac{a}{b}\Rightarrow\frac{b^2}{c^2}=\frac{a^2}{b^2}=\frac{a^2+b^2}{b^2+c^2}=\frac{ac}{c^2}=\frac{a}{c}\)

\(\Rightarrow\frac{a^2+b^2}{b^2+c^2}=\frac{a}{c}\)