a) Ta có:
a(b-c)+b(c-a)+c(a-b)
=ab-ac+bc-ab+ca-bc
=(ab-ab)+(bc-bc)+(ac-ca)
=0.
b) Ta có:
a(bz-cy)+b(cx-az)+c(ay-bx)
=abz-acy+bcx-baz+cay-cbx
=(abz-baz)+(acy-cay)+(bcx-cbx)
=0.
Cho bx-ay/c=az-cx/b=cy-bz/a. CMR x/a=y/b=z/c
Biết bz-cy/a=cx-az/b=ay-bx/c ( a,b,c khác 0). Chứng minh rằng: x/a=y/b=z/c
Cho [bz-cy]\a=[cx-az]\b=[ay-bx]\c.CMR:x\a=y\b=z\c
Cho bz-cy/a=cx-az/b=ay-bx/c.
C/m: x/a=y/b=z/c
Biết bz-cy/a =cx-az/b =ay-bx/c (a,b,c khác 0)
CMR: x/a=y/b=z/c
Cho biết : \(\dfrac{bz-cy}{a}=\dfrac{cx-az}{b}=\dfrac{ay-bx}{c}\) với a,b,c \(\ne\) 0
Chứng minh rằng \(\dfrac{x}{a}=\dfrac{y}{b}=\dfrac{z}{c}\)
Cho (bz - cy)/a = (cx - az)/b = (ay - bx)/c
CMR : x/a = y/b = z/c
Cho bz-cy/a = cx-az/b = ay-bx/c
CMR x/a = y/b = z/c
Cho bz-cy/a = cx-az/b = ay-bx/c
CMR:x/a = y/b = z/c
