\(\frac{1}{c}=\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}\right)\)
=>\(\frac{1}{c}=\frac{a+b}{2ab}\)
=> 2ab = c(a+b)
=> ab+ab = ac+bc
=> ab - bc = ac - ab
=> b(a-c) = a(c-b)
=> \(\frac{a}{b}=\frac{a-b}{c-b}\left(đpcm\right)\)
cho \(\frac{1}{c}\)=\(\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}\right)\)(với a, b, c \(\ne\)0; b\(\ne\)0)
chứng minh rằng: \(\frac{a}{b}=\frac{a-c}{c-b}\)
Cho \(\frac{1}{c}=\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}\right)\) ( với a, b, c \(\ne\)0 và b \(\ne\)c ). Chứng minh rằng : \(\frac{a}{b}=\frac{a-c}{c-b}\)
mn giúp tôi đc ko???
1:cho \(\frac{1}{c}=\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}\right)\)(với a,b,c\(\ne\)0;b\(\ne\)c) chứng minh rằng\(\frac{a}{b}=\frac{a-c}{c-b}\)
2: cho số tự nhiên n,chứng tỏ A=\(9^{n+2}+3^{n+2}-9^n+3^n⋮10\)
Cho \(\frac{1}{c}\)=\(\frac{1}{2}\)(\(\frac{1}{a}\)+\(\frac{1}{b}\)) (với a,b,c\(\ne\)0 ; b\(\ne\)c) chứng minh rằng \(\frac{a}{b}\)=\(\frac{a-c}{c-b}\)
cho \(\frac{1}{c}=\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}\right)\left(a,b,c\ne0;b\ne c\right)\)) chứng minh rằng : \(\frac{a}{b}=\frac{a-c}{c-b}\)
Cho \(\frac{1}{c}=\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}\right)\left(a,b,c\ne0,b\ne c\right)\).Chứng minh rằng\(\frac{a}{b}=\frac{a-c}{c-b}\)
Cho \(\frac{1}{c}=\frac{1}{2}.\left(\frac{1}{a}+\frac{1}{b}\right)\)(với \(a,b,c\ne0;b\ne c\)) chứng minh rằng \(\frac{a}{b}=\frac{a-c}{c-d}\)
cho \(\frac{1}{c}=\frac{1}{2}\left(\frac{1}{a}+\frac{1}{b}\right)\) với \(a,b,c\ne0,b\ne c\) chứng minh rằng \(\frac{a}{b}=\frac{a-c}{c-b}\)
Cho: \(\frac{1}{c}=\frac{1}{2}.\left(\frac{1}{a}+\frac{1}{b},\right)\left(a,b,c\ne0,b\ne c\right)\) Chứng minh rằng: \(\frac{a}{b}=\frac{a-b}{c-b}\)
