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Lời giải:
a)
$x(a-b)-x(a+b)=xa-xb-xa-xb=-2xb$
b)
$(a^2-ax+by)-(by-a^2-ax)=a^2-ax+by-by+a^2+ax=2a^2$
c)
$(a-b)(a+b)-(b-a)b=a^2-b^2-(b^2-ab)=a^2-b^2-b^2+ab=a^2-2b^2+ab$
\(a,x\left(a-b\right)-x\left(a+b\right)\)
\(=ax-bx-ax-bx=-2bx\)
\(b,\left(a^2-ax+by\right)-\left(by-a^2-ax\right)\)
\(=a^2-ax+by-by+a^2+ax=2a^2\)
\(c,\left(a-b\right)\left(a+b\right)-\left(b-a\right).b\)
\(=a^2-b^2-b^2+ab\)
\(=\left(a-b\right)^2-b^2=\left(a-b-b\right)\left(a-b+b\right)\)
\(=\left(a-2b\right).a\)
a) (m - n) (m + n) = m2 + mn - mn + n2 = m2 + n2
b) x(a - b) - x(a + b) = ax - bx - ax - bx = -2bx
c) (a2 - ax + by) - (by - a2 - ax) = a2 - ax + by - by + a2 + ax = 2a2
d) (a - b) (a + b) - (b - a)b = a2 + ab - ab - b2 - b2 + ab = a2 - 2b2 + ab
a)A = (a - b) – (a – b + c)
A=a-b-a+b-c
A=(a-a)+(b-b)-c
A=-c
b)B = (a + b + c) – (a + b - 5)
B=a+b+c-a-b+5
B=(a-a)+(b-b)+(c+5)
B=c+5
a) A = (a - b) - (a - b + c)
A = a - b - a + b - c
A = -c
b) B = (a + b + c) - (a + b - 5)
= a + b + c - a - b + 5
= c + 5
\(\left(a-b\right)\left(a+b\right)-\left(b-a\right)b\)
\(=a^2-ab+ab-b^2-b^2+ab\)
\(=a^2-b^2-b^2+ab\)
\(=a^2-2b^2+ab\)
\(=a\left(b+1\right)-2b^2\)
a,(a+b)-(a-b)+(a-c)-(a+c)
=a+b-a+b+a-c-a-c
=2b+2(-c)
b,(a+b-c)+(a-b+c)-(b+c-a)-(a-b-c)
=a+b-c+a-b+c-b-c+a-a+b+c
=2a
Ta có : a-(a-3)-(a+3)-(a-2).2 = a-a+3-a-3-2a+4 = (a - a) + (3 - 3) + 4 - (2a+a) = 4 - 3a
k nha bạn
Ta có : a-(a-3)-(a+3)-(a-2).2
= a-a+3-a-3-2a+4
= (a - a) + (3 - 3) + 4 - (2a+a)
= 4 - 3a
mình nha các bạn !!!
Giải:
\(A=\left(a+b\right)-\left(a-b\right)+\left(a-c\right)-\left(a+c\right)\)
\(\Leftrightarrow A=a+b-a+b+a-c-a-c\)
\(\Leftrightarrow A=\left(a-a+a-a\right)+\left(b+b\right)+\left(-c-c\right)\)
\(\Leftrightarrow A=2b-2c\)
\(\Leftrightarrow A=2\left(b-c\right)\)
Vậy ...
a)
A = ( a+b) - (a-b) + (a-c) - (a+c)
A = a + b - a + b + a- c - a - c
A = ( a - a + a -a) + ( b + b) + ( -c - c )
= 2b -2c
Giải:
\(\left(a^2-ax+by\right)-\left(by-a^2-ax\right)\)
\(=a^2-ax+by-by+a^2+ax\)
\(=\left(a^2+a^2\right)+\left(-ax+ax\right)+\left(by-by\right)\)
\(=2a^2+0+0=2a^2\)
Vậy ...