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

b, - ( a+b-c+d) + (a-b-c-d) = -a -b+c-d + a-b-c-d = -2b + (-2c)= -2(b+c)

1. a-c+d-c+d-d=a-2c+d
2. -a-b+c-d+a -b-c-d=-2b-2d
3. ab-ac-ad-ab-ac+ad=-2ab-2ac
4. ac+ad+bc+bd-ab-ac-bd-cd=ad+bc+bd-ab-bd-cd

tích mình với

ai tích mình

mình tích lại

thanks

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

=ad-ac+a²-c+a-d

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

=-a-b-c-d+a-b-c-d

=-2b-2c-2d

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

=-ac+ab-a²+ad-ac-ab

=ad-2ac-a²

 (a+b) . (c+d) - (a+d). (b+c)

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

=ac+bc+ad+bd-ab-db-ac-dc

=(ac-ac)+(bd-db)+bc+ad-ab-dc

=0+0+bc+ad-ab-dc

=bc+ad-ab-dc

=(ad-ab)-(dc-bc)

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

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

nhớ ủng hộ cho mình 1 đúng nhe

a) -(-a + c - d) - (c - a + d) = a - c + d - c + a - d = (a + a) - (c + c) + (d - d) = 2a - 2c

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

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

d) (b + a) + (c - d) - (c + a) - (b - d) = b + a + c - d - c - a - b + d = (b - b) + (a - a) + (c - c) - (d - d) = 0

e) (a - b) - (d + a) - (c - d) + (c + b) = a - b - d - a - c + d +  c + b = (a - a) - (b - b) - (d - d) - (c - c) = 0

f) -a + (c - b) - (c + a - b) = - a + c - b - c - a + b = (-a - a) + (c - c) - (b - b) = -2a

a ) a - c + d - c + a - d = 2a - 2c 

b )  -a - b + c - d + a - b - c - d = -2b - 2d 

 CÁC CÂU CÒN LẠI LÀM TƯƠNG TỰ NHÉ!!

1) \(=ac+ad+bc+bd-ab-ac-db-dc=ad+bc-dc-ab=d\left(a-c\right)-b\left(a-c\right)=\left(a-c\right)\left(d-b\right)\)

2) \(=ac-ad+bc-bd-ac-ad+bc+bd=2bc-2ad=2\left(bc-ad\right)\)

3) \(\left(a+b\right)\left(a+b\right)-\left(a-b\right)\left(a-b\right)=a^2+2ab+b^2-a^2+2ab-b^2=4ab\)

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

= -a - b + c - d + a - b - c - d

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

= -2b -2d