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(a-b+c)-(a+c)
= a-b+c-a-c
=(a-a)+(c-c)-b
=-b
2.( a + b ) - ( b - a ) + c
= a + b - b + a + c
=( a + a ) + ( b -b ) + c
= 2a + 0 + c
= 2a + c
mấy câu sau bn tự lm nha
1,a-b+c-a-c=-b
2,a+b-b-a+c=2a+c
3,-a-b+c+a-b-c=-2b
4,ab+ac-ab-ad=ac-ad=a(c-d)
5,ab-ac+ad+ac=ab+ad=a(b+d)
1)-(a+b-c)+(a-b-c)=a-b+c+a-b-c=-2b
2)a(b+c)-a(b+d)=a(b+c-b-d)=a(c-d)
3)a(b-c)+a(d+c)=a(b-c+d+c)=a(b+d)
chúc hok tốt :))))))
ak ở câu 1 sửa lại chút
1)-(a+b-c)+(a-b-c)=-a-b+c+a-b-c=-2b
1) (a-b+c)-(a+c)=-b=a-b+c-a-c=-b
2)(a+b)-(b-a)=2a+c=a+b-b+c+c=2c+a(ko the bang 2a+c)
3)-(a+b-c)+(a-b-c)=-a-b+c+c-b-c=-2c
tk minh nha
lam dc the thoi
( a + b ) _ ( b _ a ) + c = 2a + c
\(a+b-b+a+c=2a+c\)
\(\left(a+a\right)+\left(b-b\right)+c=2a+c\)
\(2a+0+c=2a+c\)
\(2a+c=2a+c\Rightarrowđpcm\)
- ( a + b _ c ) + ( a _ b _c ) = - 2b
\(-a-b+c+a-b-c=-2b\)
\(\left(-a+a\right)+\left(-b-b\right)+\left(c-c\right)=-2b\)
\(0-2b+0=-2b\)
\(-2b=-2b\Rightarrowđpcm\)
a nhân ( b+ c ) _ a nhân ( b + d ) = a nhân ( c _ d )
\(ab+ac-ab+ad=a.\left(c-d\right)\)
\(a.\left(b+c-b+d\right)=a.\left(c-d\right)\)
\(a.\left(c-d\right)=a.\left(c-d\right)\Rightarrowđpcm\)
a nhân ( b _ c ) + a nhân ( d + c ) = a nhân ( b + d )
\(ab-ac+ad+ac=a.\left(b+d\right)\)
\(a.\left(b-c+d+c\right)=a.\left(b+d\right)\)
\(a.\left(b+d\right)=a.\left(b+d\right)\)
chúc bạn học tốt!!!
( a _ b + c ) _ ( a+ c ) = - b
\(a-b-c-a-=-b\)
\(\left(a-a\right)-c-b=-b\)
\(0-c-b=-b\)
\(-b=-b\Rightarrowđpcm\)
\(a,\left(a-b+c\right)-\left(a+c\right)=a-b+c-a-c=-b\)
\(b,\left(a+b\right)-\left(b-a\right)+c=a+b-b+a+c=2a+c\)
\(c,-\left(a+b-c\right)+\left(a-b-c\right)=-a-b+c+a-b-c=-2b\)
\(d,a\left(b+c\right)-a\left(b+d\right)=ab+ac-ab-ad=ac-ad=a\left(c-d\right)\)
\(e,a\left(b-c\right)+a\left(d+c\right)=ab-ac+ad+ac=ab+ad=a\left(b+d\right)\)
a) (a - b + c) - (a + c)
= a - b + c - a - c
= (a - a) - b + (c - c)
= -b
b) (a + b) - (b - a) + c
= a + b - b + a + c
= 2a + (b - b) + c
= 2a + c
c) - (a + b - c) + (a - b - c)
= -a - b + c + a - b - c
= (-a + a) - (b + b) + (c - c)
= -2b
d) a(b + c) - a(b + d)
= ab + ac - ab - ad
= (ab - ab) + (ac - ad)
= ac - ad
= a(c - d)
e) a(b - c) + a(d + c)
= a(b - c + d + c)
= a[b - (c - c) + d]
= d(b + d)
(a - b + c) - (a + c) = a - b + c - a - c = -b (đpcm)
(a + b) - (b - a) + c = a + b - b + a + c = 2a + c (đpcm)
-(a + b - c) + (a - b - c) = -a - b + c + a - b - c = -2b (đpcm)
a.(b + c) - a.(b + d) = a.(b + c - b - d) = a.(c - d) (đpcm)
a.(b - c) + a.(d + c) = a.(b - c + d + c) = a.(b + d) (đpcm)