a(b+c) - a(b+d)=a(c-d)
VP= a(b+c) - a(b+d)
= ab+ac-ab-ad
= ac-ad
=a(c-d)
Suy ra VP=VT
a(b-c)+a(d+c)=a(b+d)
VP= a(b-c)+a(d+c)
= ab-ac+ad+ac
= ab+ad
= a(b+d)
Suy ra VP=VT
Chứng tỏ:a/b>c/d suy ra a.d>c.d với a;b;c;d dương
CHỨNG MINH ĐẲNG THỨC
A) a.(b+c) - a.(b+d)= a.(c-d)
B) a.(b-c) + a.(d-c)= a.(b+d)
C) a.(b-c) - a.(b+d)= -a.(c+d)
D) (a+b).(c+d)-(a+b).(b+c)= (a-c).(d-b)
Chứng minh:
a) (a-b)+(c-d)=(a+c)-(b+d)
b) a(b+c)-b(a-c)=c(a+b)
c) (a+b)(c+d)-(a+d)(b+c)=(a-c)(d-b)
Cho a;b;c;d thuộc Z. Chứng minh đẳng thức sau
1) a( b+c) - b(a-c) = ( a+b) c
2)a (b - c)- a (b+d)= - a (c+d)
3) ( a+b)(c+d) - (a + d)(b+c) = (a-c( d - b)
chứng tỏ rằng
1, a(b+c)-b(a-c)=(a+b)c
2, a(b-c)-a(b+d)=-a(c+d)
3, (a+b)(c+d)-(a+d)(b+c)=(a-c)(d-b)
chứng tỏ
a) a(b-c)-a(b+d)=-a(c+d)
b) (a+b)(c+d)-(a+d)(b+c)=(a-c)(d-b)
1.Chứng tỏ
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)
chứng tỏ:
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)
Chứng tỏ:
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 )
