Question

[Trần Hà Phương]

Tính tổng a

A=(a+b)+(c−d)−(c+a)−(b−d)

Answer 1

[Lê Nguyên Hạo]

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

\(A=a+b+c-d-c-a-b+d\)

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

\(A=0\)

Answer 2

[Uyển Nghi]

 A=(a+b)+(c−d)−(c+a)−(b−d)

   = a + b + c - d - c - a - b + d

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

   = 0