Chứng tỏ
1. ( a - b + c) - ( a + c) = -b
2. ( a + b) - ( b - a) + c = 2a + c
3. -( a + b - c) + ( a -b -c ) = -2b
4. a ( b + c ) - a ( b + d) = a ( c - d)
5. a ( b - c ) + a ( d + c) = a ( b + d)
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\(\text{ (a-b+c)-(a+c)}=a-b+c-a-c=\left(a-a\right)-b+\left(c-c\right)=-b\)
\(\left(a+b\right)-\left(b-a\right)+c=a+b-b+a+c=2a+c\)
\(-\left(a+b-c\right)+\left(a-b-c\right)=-a-b+c+a-b-c=-2b\)
\(a\left(b+c\right)-a\left(b+d\right)=ab+ac-ab+ad=ac+ad=a\left(c+d\right)\)
\(a\left(b-c\right)+a\left(d+c\right)=a\left(b-c+d+c\right)=a\left(b+d\right)\)
1,(a-b+c)-(a+c)=a-b+c-a-c=-b
2,(a+b)-(b-c)+c=a+b-b+c+c=2c+a (không thể bằng 2a+c đc)
3,-(a+b-c)+(a-b-c)=-a-b+c+a-b-c=-2b
1) (a-b+c)-(a+c)=a-b+c-a-c=-b (đpcm)
2) (a+b)-(b-a)+c=a+b-b+a+c=2a+c (đpcm)
3) -(a+b-c)+(a-b-c)=-a-b+c+a-b-c=-2b (đpcm)
4) a(b+c) -a(b+d)=ab+ac-ab-ad=ac-ad=a(c-d) (đpcm)
5) a(b-c)+a(d+c)=ab-ac+ad+ac=ab+ad=a(b+d) (đpcm)
CHÚC BẠN HỌC TỐT NHÉ!
\(\left(a-b+c\right)-\left(a+c\right)=-b\)
\(a-b+c-a-c=-b\)
\(-b=-b\left(đpcm\right)\)
\(\left(a+b\right)-\left(b-a\right)+c=2a+c\)
\(a+b-b+a+c=2a+c\)
\(2a+c=2a+c\left(đpcm\right)\)
\(-\left(a+b-c\right)+\left(a-b-c\right)=-2b\)
\(-a-b+c+a-b-c=-2b\)
\(-2b=-2b\left(đpcm\right)\)
lm cx dễ thoi , bn lm tiếp nha !
1,(a-b+c)-(a+c)
=a-b+c-a-c
=(a-b)-b+(c-c)
=0-b+0
=-b(đpcm)
2,(a+b)-(b-a)+c
=a+b-b+a+c
=(a+a)+(b-b)+c
=2a+0+c
=2a+c(đpcm)
3,-(a+b-c)+(a-b-c)
=-a-b+c+a-b-c
=(-a+a)-b-b+(c-c)
=0-b-b+0
=-b-b
=-2b(đpcm)
4,a(b+c)-a(b+d)
=ab+ac-ab+ad
=(ab-ab)+ac+ad
=0+ac+ad
=ac+ad
=a(c+d)(đpcm)
5,a(b-c)+a(d+c)
=ab-ac+ad+ac
=(-ac+ac)+ab+ad
=0+ab+ad
=ab+ad
=a(b+d)(đpcm)
1. ( a - b + c ) - ( a + c )
=> a - b + c - a - c
=> ( a - a ) - b + ( c - c )
=> 0 - b + 0
=> -b ( đpcm ).
2. ( a + b ) - ( b - a ) + c
=> a + b - b + a + c
=> ( a + a ) + ( b - b ) + c
=> 2a + c ( đpcm )
1/ ( 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 + c
3/ -( a + b - c ) + ( a-b-c )
= - ( a + b - c ) + a - b - c
= -a - b + c + a - b - c
= -a + a + c -c - b - b
= -2b
4 / a ( b+ c) - a ( b+ d )
= ab + ac - ab + ad
= a ( b + c - b + d )
= a ( c + d)
Cứ lm thế bn nhé !
1 , ( a-b+c ) - ( a+c)
= a-b+c-a-c
= a-a + c-c -b
=( a-a ) + ( c-c ) -b
=0+0-b
=-b
b , ( a+b ) -( b-a )+c
=a+b -b +a+c
= a+a +b-b+c
= ( a+a ) + ( b-b ) +c
=2a +0 +c
=2a +c
1. (a - b + c ) - (a +c) = -b 2. ( a + b ) - (b - a) + c = 2a + c
VT: = a - b + c - a - c VT: =a + b - b + a + c
\(\Leftrightarrow\)( a - a ) +( c - c ) - b \(\Leftrightarrow\)(a + a ) + (b - b ) + c
\(\Leftrightarrow\)0 + 0 - b \(\Leftrightarrow\)2a + 0 +c
\(\Leftrightarrow\)-b = VP \(\Leftrightarrow\)2a + c = VP
vậy (a - b + c ) - (a +c) = -b Vậy ( a + b ) - (b - a) + c = 2a + c
3.( a + b ) - (b - a) + c = 2a + c 4. a ( b + c ) - a ( b + d ) = a ( c - d)
VT: = -a - b + c + a - b - c VT = ab + ac - ab - ad
\(\Leftrightarrow\)(-a + a) + (-b - b ) + (c - c ) \(\Leftrightarrow\)( ab - ab ) + ( ac - ad )
\(\Leftrightarrow\) 0 + (-2b) + 0 \(\Leftrightarrow\)0 + ac - ad
\(\Leftrightarrow\)-2b = VP \(\Leftrightarrow\) a . (c - d) = VP
Vậy : ( a + b ) - (b - a) + c = 2a + c Vậy : a ( b + c ) - a ( b + d ) = a ( c - d)
5. a ( b - c ) + a ( d + c ) = a ( b + d)
VT = ab - ac + ad + ac
\(\Leftrightarrow\)( -ac + ac ) +( ab + ad )
\(\Leftrightarrow\)ab + ad
\(\Leftrightarrow\) a .( b + d) = VP
Vậy a ( b - c ) + a ( d + c ) = a ( b + d)
học tốt nhé bạn ^^
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