Пошаговое объяснение:
80 . 1) x - ( x - y )/2 + ( x + y )/4 = [ 4x - 2( x - y ) + ( x + y ) ] /4 =
= ( 4x - 2x + 2y + x + y )/4 = ( 3x + 3y )/4 = 3( x + y )/4 ;
2) 3/x - 2 - 5/x = ( 3 - 2x - 5 )/x = ( - 2x - 2 )/x = - 2( x + 1 )/x ;
3) 3 - ( 2x - y )/4 + ( x + 4y )/12 = [ 36 - 3( 2x - y ) + ( x + 4y ) ]/12 =
= ( 36 - 6x + 3y + x + 4y )/12 = ( 36 - 5x + 7y )/12 ;
4) ( 6a - 4b )/5 - ( b + 7a )/3 - 2 = [ 3( 6a - 4b ) -5( b + 7a ) - 30 ]/15 =
= ( 18a - 12b - 5b - 35a - 30 )/15 = ( - 17a - 17b - 30 )/15 .( привітГрузії ) .
