Question

Thu gọn ; A=  a( b - c ) + c ( a - b ) - b ( a - c ) - ab

 

Answer 1

A = ab - ac + ac - bc - ab + bc - ab

A = - ab 

Answer 2

A = a ( b - c ) + c ( a - b ) - b ( a - c ) - ab

   = ab - ac + ac - bc - ab + bc - ab

   = - ab

Vậy A = -ab

Answer 3

\(A=a\left(b-c\right)+c\left(a-b\right)-b\left(a-c\right)-ab\)

\(A=ab-ac+ac-bc-ab+bc-ab\)

\(A=ab\)