Question

[Nguyen Minh Thu_712]

Chứng minh đẳng thức sau:

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

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

Answer 1

[hoang nguyen truong giang]

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