F = 18 ft.
The law of cosines states
c² = a² + b² - 2ab cos C
Using our information, we have
c² = 23² + 16² - 2(23)(16)cos 52
c² = 529 + 256 - 736cos 52
c² = 785 - 736cos 52
c² = 331.8732
Taking the square root of both sides, we have
c = √331.8732 = 18.22 ≈ 18
a = ( 1 , 6 )
b = ( 4 , 9 )

Now just need to put the coordinates in the above equation :



And we're done...♥️♥️♥️♥️♥️
A. Judy made a mistake between Steps 1 and 2
To factor

, you have to factor it as

, not

, because that will leave an extra 6x because of 8x - 2x.
Answer: I gave the evaluate answer and the differentiate w.r.t x answer. Sorry for caps.
Step-by-step explanation: EVALUATE x4n−3
DIFFERENTIATE W.R.T. X (4n−3)x4(n−1)