1/ (a-b+c) - (a+c) = a-b+c-a-c = -b
2/ (a+b) - (b-a) + c = a + b - b + a + c = 2a + c
3/ - (a+b-c) + (a-b-c) = -a - b + c + a - b - c = - 2b
4/ a(b+c) - a(b+d) = a(b+c-b-d) = a(c-d)
5/ a(b-c) + a(d+c) = a(b-c+d+c) = a(b+d)
1/ (a-b+c) - (a+c) = a-b+c -a-c
= (a-a) +(c-c) -b
= 0+0-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+a) + (-b-b) +(c-c)
= 0 +(-2b)+ 0
= -2b
4/ a (b+c)- a(b+d) = ab+ac - ab-ad
= (ab-ab) +(ac-ad)
= 0+ a.(c-d)
= a.(c-d)
5/ a(b-c) + a(d+c) = ab-ac + ad +ac
= (-ac+ac) + (ab+ad)
= 0+ a.(b+d)
= a.(b+d)
1/ Ta có:
(a - b + c) - (a + c) =a - b + c - a - c
=(a - a) + (c - c) + (-b)
=0 + 0 + (-b)
=-b
2/ Ta có:
(a+b)-(b-a)+c=a+b-b+a+c=(a+a)+(b-b)+c=2a+0+c=2a+c
3/ Ta có:
-(a+b-c)+(a-b-c)=-a-b+c+a-b-c=(-a+a)+(-b-b)+(c-c)=0+(-2b)+0=-2b
4/ Ta có:
a(b+c)-a(b+d)=ab+ac-ab-ad=(ab-ab)+(ac-ad)=0+(ac-ad)=ac-ad=a(c-d)
5/ Ta có:
a(b-c)+a(d+c)=ab-ac+ad+ac=(ab+ad)+(-ac+ac)=a(b+d)+0=a(b+d)