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.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)
Chứng tỏ
1,(a-b+c)-(a+c)=-b
2,(a+b)-(b-c)+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)
Bài 18: 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)
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)
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)
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)
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)
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)
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)
