Question

Bài 1 : Thu gọn biểu thức

a) (a-b-d)+(b-a-d)

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

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

 

 

Answer 1

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

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

\(=0-2d\)

\(=-2d\)

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

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

\(=-2a+2b\)

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

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

\(=c-b\)

Answer 2

a ) \(\left(a-b-d\right)+\left(b-a-d\right)=a-b-d+b-a-d=-2d\)

b ) \(-\left(a-b+c\right)-\left(a-b-c\right)=-a+b-c-a+b+c=-2a+2b=2\left(-a+b\right)\)

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