Question

Chứng minh đẳng thức sau:

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

Answer 1

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

= a-b+c-d-a-c

= 0+0-b-d

= -(b+d) (ĐPCM)

Answer 2

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

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

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

\(=-b-d\)

\(=-\left(b+d\right)=VP\left(đpcm\right)\)