Answer:
1. Collinear is a two line that lies on a same line (Refer pic 1)
2. Intersecting is a two line that meets at a point. The point called intersecting point. Refer pic 2
3. Parrallel is a non collinear line that move to the same direction and will never intersect to each other. Refer pic 3
4. Non collinear is a line that is not lies on the same line. This lines will intersect to each other at one point. Refer pic 4
Recall that for 3 vectors 
, all in 
, the vector triple product
So
Also recall the scalar triple product,
which gives the signed volume of the parallelipiped generated by the three vectors . When either 
or 
, the parallelipepid is degenerate and has 0 volume, so
and the above reduces to
so that
![(u\times v)\cdot[(v\times w)\times(w\times u)]=(u\times v)\cdot((v\times w)\cdot u)w](https://tex.z-dn.net/?f=%28u%5Ctimes%20v%29%5Ccdot%5B%28v%5Ctimes%20w%29%5Ctimes%28w%5Ctimes%20u%29%5D%3D%28u%5Ctimes%20v%29%5Ccdot%28%28v%5Ctimes%20w%29%5Ccdot%20u%29w)
The scalar triple product has the following property:
Since 
is a scalar, we can factor it out to get
and by the property above we have
and so we end up with
![[u\cdot(v\times w)]^2](https://tex.z-dn.net/?f=%5Bu%5Ccdot%28v%5Ctimes%20w%29%5D%5E2)
as required.
Answer:
0.21428571428
Step-by-step explanation:
hope it helps
The answer is 21, 21 is the value of x
