Ta có:

\(\frac{a+b}{a-b}=\frac{c+a}{c-a}\)

=> (c-a)(a+b) = (c+a)(a-b)

=> ca + cb - a² -ab = ca - cb + a² -ab

=> ca + cb - a² - ab - ca + cb - a²+ ab=0

=> (ca - ca) + (cb + cb) - (a² + a²) - (ab - ab) =0

=> 2bc - 2a² =0

=> 2bc = 2a²

=> bc= a²

Vậy khi (a+b)/(a-b)= (c+a)/(c-a) thì a² = bc

| 3x - 2 | = 7

=> 3x - 2 ∈ { -7 ; 7 }

=> 3x ∈ { -5 ; 9 }

=> x ∈ \(\left\{\frac{-5}{3};3\right\}\)

/ 3x - 2 / = 7

---> 3x - 2 \(\in\)( 7 ; -7 )

---> 3x \(\in\)( 9 ; -5 )

---> x \(\in\)( 3 ; -5/3 )

xin tiick

sửa \(\frac{x+1}{99}+\frac{x+3}{97}=\frac{x+2}{98}+\frac{x+4}{96}\)

\(\Leftrightarrow\frac{x+1}{99}+1+\frac{x+3}{97}+1=\frac{x+2}{98}+1+\frac{x+4}{96}+1\)

\(\Leftrightarrow\frac{x+100}{99}+\frac{x+100}{97}-\frac{x+100}{98}-\frac{x+100}{96}=0\)

\(\Leftrightarrow\left(x+100\right)\left(\frac{1}{99}+\frac{1}{97}-\frac{1}{98}-\frac{1}{96}\ne0\right)=0\Leftrightarrow x=-100\)

nhanh nghen

=\(\frac{7^3\times5^8}{7^2\times5^8}=7\)

xin tiick

ai chỉ mình với:)

CM GÓC LÀ SAO

6/-13 VÌ 9>6/11>6/13

          <=>6/-13>-6/12>-9

là sao

mọi người ơi mình cần gấp làm giúp mình với

\(\Rightarrow x< \frac{2}{3}+\frac{3}{4}\)

\(\Rightarrow x< \frac{17}{12}\)

\(x-\frac{3}{4}< \frac{2}{3}\)

\(\Rightarrow x< \frac{2}{3}+\frac{3}{4}\)

\(\Rightarrow x< \frac{17}{12}\)