Answer:

Step-by-step explanation:
Using the addition formulae for cosine
cos(x ± y) = cosxcosy ∓ sinxsiny
---------------------------------------------------------------
cos(120 + x) = cos120cosx - sin120sinx
= - cos60cosx - sin60sinx
= -
cosx -
sinx
squaring to obtain cos² (120 + x)
=
cos²x +
sinxcosx +
sin²x
--------------------------------------------------------------------
cos(120 - x) = cos120cosx + sin120sinx
= -cos60cosx + sin60sinx
= -
cosx +
sinx
squaring to obtain cos²(120 - x)
=
cos²x -
sinxcosx +
sin²x
--------------------------------------------------------------------------
Putting it all together
cos²x +
cos²x +
sinxcosx +
sin²x +
cos²x -
sinxcosx +
sin²x
= cos²x +
cos²x +
sin²x
=
cos²x +
sin²x
=
(cos²x + sin²x) = 
Diagonal of a square is √2a
so,
√2 a = 12
a= 12/√2
and.. perimeter of a square is 4a
so,
peri = 4*12/√2
= 48/√2
=33.94cm
If they are in the same line yes. If they aren't then its considered non-collinear.
Answer:
Dont know
Step-by-step explanation:
I dont know Archer's equation but the answer for Jenna equatiok is x=10