(cos Ф -cos Ф)² + (cos Ф + cos Ф)²
Firstly: (cos Ф -cos Ф)² = 0² = 0
Secondly :(cos Ф + cos Ф)² = (2cos Ф)². = 4. (cos Ф)² = 4cos² Ф
Mind you when you raise a cosine (or sin or tan...) to the n power, the n power should affect the cosine only and NOT the angle Ф
Parallel lines always have the same slope. In fact that is the definition of parallel lines :P (Technically they have the same slope and different y-intercepts, because parallel lines can never intersect...)
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This is the answerrrrrrrrr
Answer:
Presumably you're solving for x here? Without further information we'll assume that.
With that in mind, x is approximately equal to 0.86 and -0.46
Step-by-step explanation:
Let's start by putting it in the usual ax² + bx + c format.

let's solve it. First we'll multiply both sides by five, making the first term a perfect square:

Now we'll add 11 to both sides:

Which makes the left side a perfect square:

And now we can solve for x:

Note that there's no apparent way of drawing the ± symbol when editing equations, so take that + sign as actually being ±.
That gives us two answers:

I believe the answer to your question is three you have to be three usually always three