\(S=\frac{105}{abc+ab+a}+\frac{b}{bc+b+1}+\frac{a}{ab+a+105}\)

\(S=\frac{abc}{abc+ab+a}+\frac{b}{bc+b+1}+\frac{a}{ab+a+abc}\)

\(S=\frac{abc}{a\left(bc+b+1\right)}+\frac{b}{bc+b+1}+\frac{a}{ab+a+abc}\)

\(S=\frac{bc+b+1}{bc+b+1}=1\)

1 nha bn

1 nhé bn

= 4a + 4b = 4(a + b) = 4 * 105 = 420 

420 nhe

có đúng ko đấy 

105x4=420

kb nha

dễ bạn chỉ cần lấy đó nhân cho 4 là ok thôi vì có 4 a+b mà =420 nha

420=a=....................................

\(a,b=25\)bn nhé

   a + a + a + a + a + b + b + b + b + b 

= ( a + b ) + ( a + b ) + ( a + b ) + ( a + b ) + ( a + b )

= 105 + 105 + 105 + 105 + 105

= 105 x 5

= 525

a + a + a + a + a + b + b + b + b + b 

=( a + b ) + ( a + b ) + ( a + b ) + (a + b ) + ( a + b )

= 105 + 105 + 105 + 105 + 105

= 525

=  5 x a + 5 x b

= 5 x ( a + b )

= 5 x 105

= 525

cảm en bạn hen

 a + a + a + a + a + b + b + b + b + b 

= ( a + b ) + ( a + b ) + ( a + b ) + ( a + b ) + ( a + b )

= 105 + 105 + 105 + 105 + 105

= 105 x 5

=     525

Ta có:

\(\dfrac{a+104}{a-104}=\dfrac{a-104+208}{a-104}=1+\dfrac{208}{a-104}=\dfrac{b+105}{b-105}=\dfrac{b-105+210}{b-105}=1+\dfrac{210}{b-105}\)

\(\Rightarrow\dfrac{208}{a-104}=\dfrac{210}{b-105}\)

\(\Rightarrow\dfrac{a-104}{b-105}=\dfrac{208}{210}=\dfrac{104}{105}\)

\(\Rightarrow\dfrac{a-104}{104}=\dfrac{b-105}{105}\)

\(\Rightarrow\dfrac{a}{104}-1=\dfrac{b}{105}-1\)

\(\Rightarrow\dfrac{a}{104}=\dfrac{b}{105}\left(đpcm\right)\)