Question

Phá ngoặc rồi thu gọn

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

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

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

Answer 1

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

\(=ab-ac-ad-ab-ac+ad\)

\(=-2ac\)

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

\(=ac+ad+bc+bd-ab-ac-bd-cd\)

\(=ad+bc-ab-cd\)

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

\(=ac-ad+bc-bd-ac-ad+bc+bd\)

\(=-2ad+2bc\)

\(=-2\left(ad-bc\right)\)