Toán Lớp 6: Đơn giản các biểu thức sau
a) (a + b − c) − (b − c + d)
b) −(a − b + c) + (a − b + d)
c) −(a + b) − (−a − b + c)
d) (a − b) − (c − b) − (a − c)
e) (b + a) + (c − d) − (c + a) − (b − d)
f) (a − b) − (d + a) − (c − d) + (c + b)
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=a+b-c-b+c-d
=(b-b)+(c-c)+(a-d)
=0+0+a-d=a-d
b)−(a − b + c) + (a − b + d)
=-a+b-c+a-b+d
=(a-a)+(b-b)+(d-c)
=d-c
c)−(a + b) − (−a − b + c)
=-a-b+a+b-c
=(a-a)+(b-b)-c
=-c
d)(a − b) − (c − b) − (a − c)
=a-b-c+b-a+c
=(a-a)+(b-b)+(c-c)
=0
e) (b + a) + (c − d) − (c + a) − (b − d)
=b+a+c-d-c-a-b+d
=(b-b)+(a-a)+(c-c)+(d-d)
=0
f)(a − b) − (d + a) − (c − d) + (c + b)
=a-b-d-a-c+d+c+b
=(a-a)+(b-b)+(c-c)+(d-d)
=0