Question

thu gọn các tổng sau
a.-(a-b-c)+(a-b-c)
a.(a-b)+(b-c)-(-c+a)
a.(a+b-c)+(a+b)-(a-b-c)
a.(-a+b-c)+(a+b)-(a+b)-(a-b+c)

Answer 1

a: \(=-a+b+c+a-b-c=0\)

b: \(=a+b+b-c+c-a=2b\)

c: \(=a+b-c+a+b-a+b+c=a+3b\)

Answer 2

a1) \(-\left(a-b-c\right)+\left(a-b-c\right)=-a+b+c+a-b-c=0\)

a2) \(\left(a-b\right)+\left(b-c\right)-\left(-c+a\right)=a-b+b-c+c-a=0\)

a3) \(\left(a+b+c\right)+\left(a+b\right)-\left(a-b-c\right)=a+b+c+a+b-a+b+c=a+3b+2c\)a4) \(\left(-a+b-c\right)+\left(a+b\right)-\left(a+b\right)-\left(a-b+c\right)=-a+b-c-a+b-c+\left(a+b-a-b\right)=-2a+2b-2c\)