Question

B1:chứng minh rằng

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

B2:CMR

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

 

Answer 1

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

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

Answer 2

B1:

Ta có: a-(-b-c)=a-(-b)-(-c)=a+b+c=a+(b+c)

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

=>ĐPCM

B2:

Ta có: -(a-b)+(c-d)=-a-(-b)+c+(-d)=-a+b+c-d=b+c-a-d=b+c-a-(+d)=(b+c)-(a+d)

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

=>ĐPCM