a)(a – b + c) – (a + c) = -b
b) (a + b) – (b – a) + c = 2a + c
c)- (a + b – c) + (a – b – c) = -2b
d)a(b + c) – a(b + d) = a(c – d)
e)a(b – c) + a(d + c) = a(b + d)
f) a.(b – c) – a.(b + d) = -a.( c + d)
h) (a + b).( c + d) – (a + d).( b + c) = (a – c). (d – b)
a)(a – b + c) – (a + c) = -b b) (a + b) – (b – a) + c = 2a + c c)- (a + b – c) + (a – b – c) = -2b d)a(b + c) – a(b + d) = a(c – d) e)a(b – c) + a(d +
By Samantha
Đáp án:
VT=Vế trái
VP=Vế phải
.
`a)VT=(a-b+c)-(a+c)`
`=a-b+c-a-c`
`=(a-a)-b+(c-c)`
`=-b=VP`
`→VT=VP(đpcm)`
`b)VT=(a+b)-(b-a)+c`
`=a+b-b+a+c`
`=(a+a)+(b-c)+c`
`=2a+c=VP`
`→VT=VP(đpcm)`
`c)VT=-(a+b-c)+(a-b-c)`
`=-a-b+c+a-b-c`
`=(-a+a)+(-b-b)+(c-c)`
`=-2b=VP`
`→VT=VP(đpcm)`
`d)VT=a(b+c)-a(b+d)`
`=ab+ac-ab-ad`
`=(ab-ab)+(ac-ad)`
`=a(c-d)=VP`
`→VT=VP(đpcm)`
`e)VT=a(b-c)+a(d+c)`
`=ab-ac+ad+ac`
`=(ab+ad)+(-ac+ac)`
`=a(b+d)=VP`
`→VT=VP(đpcm)`
`f)VT=a(b-c)-a(b+d)`
`=ab-ac-ab-ad`
`=(ab-ab)+(-ac-ad)`
`=-a(c+d)=VP`
`→VT=VP(đpcm)`
`h)VT=(a+b)(c+d)-(a+d)(b+c)`
`=ac+ad+bc+bd-(ab+ac+bd+cd)`
`=ac+ad+bc+bd-ab-ac-bd-cd`
`=ad+bc-ab-cd`
`VP=(a-c)(d-b)`
`=ad-ab-cd+bc`
`→VT=VP(đpcm)`
Đáp án:
Giải thích các bước giải:
a)a-b+c-a-c+b=0 <=>0
b)a+b-b+a+c-2a-c=0<=>0=0
c)-a-b+c+a-b-c+2b<=>0=0
d)ab+ac-ab-ad=ac-ad
<=>ac-ad-ac+ad=0
<=>0=0
e) ab-ac+ad+ac=ab+ad
=>ab+ad-ab-ad=0
=>0=0
f)ab-ac-ab-ad=-ac-ad
=>-ac-ad+ac+ad=0
=>0=0
h)ac+ad+bc+bd-ab-ac-db-dc=ad=ab-cd+cb
=>0=0