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-a-b+c-a+b+c=-a+-b+c-a+b+c
=(-a+a)+(-b+b)+(c-c)
=0+0+0
=0
Ta có:
a(b-c)-c(b-d)+a(c+d)+bc
=ab-ac-bc+cd+ac+ad+bc
=ab+cd+ad
Hok tốt !!!
a( b-c ) - c(b-d) + a(c+d) +bc
= ab -ac - bc + cd + ac + ad + bc
=ab + cd + ad
a)= a-c+d-c+a-d
=2a-2c=2(a-c)
b)=-a-b+c-d+a-b-c-d
=-2b-2d
=2.(-b)-2d=2(-b-d)
c)=ab-ac-ad-ab-ac+ad
=-2.ac
Trình bày rõ xíu
a/ \(a-\left(a-b+c\right)\)
\(=a-a+b-c\)
\(=b-c\)
b/ \(\left(a+b-c\right)-\left(a-b+c\right)\)
\(=a+b-c-a+b-c\)
\(=2b-2c\)
\(=2\left(b-c\right)\)
c/ \(\left(a+b-c\right)-\left(a-b-c\right)+\left(-b\right)\)
\(=a+b-c-a+b+c-b\)
\(=b\)
a-(a-b+c)=a-a+b-c=b-c
(a+b-c) - ( a-b+c)= a+b-c-a+b-c=2b-2c
(a+b-c) - (a-b-c) +(-b)= a+b-c-a+b+c+ (-b)=2b+(-b)=b
xong!!!!!!!
A=a(2b-c)-b(a+c)-(c+b)
=2ab-ac-ab-bc-c-b
=(2ab-ab)-ac-bc-c-d
=ab-ac-bc-c-b
B=(a+3b)(c-d)-(3a-d)(b+c)-2c(b-a)+2b(a+d)
=a.(c-d)+3b.(c-d)-3a.(b+c)+d.(b+c)-2bc+2ac+2ab+2bd
=ac-ad+3bc-3bd-3ab-3ac+bd+cd-2bc+2ac+2ab+2bd
=(-3ab+2ab)+(3bc-2bc)+(ac-3ac+2ac)-ad+(-3bd+bd+2bd)+cd
=-ab+bc-ad+cd
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)+(c-c)+(-b-b)+(-d-d)
= -2b-2d
c, (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-bd-ac-cd
= (ac-ac)+(bd-bd)+(bc-ab)+(ad-cd)
= b(c-a)+d(a-c)
= b(c-a)-d(c-a)
= (b-d)(c-a)
d, a(b-c-d)-a(b+c-d)
= a[(b-c-d)-(b+c-d)]
= a[b-c-d-b-c+d]
= a[(b-b)+(-c-c)+(-d+d)]
= -2ca
Chúc bạn học tốt.....
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)
= 0 + 0 + 2c + 0
= 2c
b ) - ( a - b + c ) - ( a + b - c ) + ( - a + c )
= (-a) + b - c - a - b + c + (-a) + c
= [(-a) + (-a) + (-a)] + (b - b) + [(-c) + c + c]
= [(-a) . 3] + 0 + c
= [(-a) . 3] + c
a) ( a + b + c ) - ( b - c + d )
= a + b + c - b + c - d
= a + 2c - d
b) -(-a - b + c ) + ( a - b + d )
= a + b - c + a - b + d
= 2a - c + d
c) ( a + b ) - ( -a + b - c )
= a + b + a - b + c
= 2a + c
d) -(a + b) + ( a + b + c )
= -a - b + a + b + c
= c
Học tốt~