(a+b 2b) ------ - ----- * (a+b) a a+b помогите))
1) ( a + b )/a - ( 2b )/( a + b ) = ( ( a + b )^2 - 2ab ) / ( a( a + b )) = ( a^2 + b^2 )/( a( a + b )) 2) [( a^2 + b^2)/( a( a + b ) ] : ( a + b ) = ( a^2 + b^2 ) / ( a( a + b )^2 )