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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, \(\left(a+b+c+d\right)-\left(a-b+c-d\right)\)
\(=a+b+c+d-a+b-c+d=2b+2d\)
\(=2.\left(b+d\right)\)
b, \(\left(-a+b-c+d\right)+\left(a+d\right)+\left(-b+c\right)\)
\(=-a+b-c+d+a+d-b+c\)
\(=2d\)
c, \(-\left(a-b-d\right)+\left(b-c+d\right)-\left(-c+b-d\right)\)
\(=-a+b+d+b-c+d+c-b+d\)
\(=-a+b+3d\)
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) = 2b + 2d = 2.(b + d)
b,(-a+b-c+d)+(a+d)+(-b+c) = -a + b - c + d + a + d - b + c = (-a + a) + (b - b) + ( -c + c) + (d + d) = 2d
c,-(a-b-d)+(b-c+d)-(-c+b-d)= -a + b + d + b - c + d + c - b + d = -a + (b + b - b) + (-c + c) + ( d + d + d) = -a + b + 3d
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!!
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
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+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 + 0 - 2d
= -2d
Ý b, c em xem lại xem sao chỗ chữ cái viết hoa chỗ lại viết thường là sao em nhỉ?
a) \(\left(a+b-c\right)-\left(b-c+d\right)\)
\(=a+b-c-b+c-d\)
\(=a+b-b-c+c-d\)
\(=a-d\)
b) \(-\left(a-b+c\right)+\left(a-b+d\right)\)
\(=\left(-a\right)+b-c+a+b-d\)
\(=\left(-a\right)+a+b+b-c-d\)
\(=2b-c-d\)
c) \(\left(a+b\right)-\left(-a+b-c\right)\)
\(=a+b+a-b+c\)
\(=a+a+b-b+c\)
\(=2a+c\)
d) \(-\left(a-b-c\right)+\left(a-b-c\right)\)
\(=-a+b+c+a+b+c\)
\(=-a+a+b+b+c+c\)
\(=2b+2c\)
(chắc hơi sai... > . < ...)