Answer:
d
Step-by-step explanation:
I think it is (xy). Hope that is right.
Answer:

Step-by-step explanation:
Factorise the denominator of the second fraction
y² - 1 = (y - 1)(y + 1) ← difference of squares
To obtain a common denominator
multiply numerator/ denominator of first fraction by (y + 1)
=
-
← subtract numerators leaving the common denominator
= 
= 
=
← cancel common factor (y - 1) on numerator/denominator
= 
we know there are 180° in π radians, how many degrees then in -3π/10 radians?
![\bf \begin{array}{ccll} degrees&radians\\ \cline{1-2} 180&\pi \\\\ x&-\frac{3\pi }{10} \end{array}\implies \cfrac{180}{x}=\cfrac{\pi }{~~-\frac{3\pi }{10}~~}\implies \cfrac{180}{x}=\cfrac{\frac{\pi}{1} }{~~-\frac{3\pi }{10}~~} \\\\\\ \cfrac{180}{x}=\cfrac{\pi }{1}\cdot \cfrac{10}{-3\pi }\implies \cfrac{180}{x}=-\cfrac{10}{3}\implies 540=-10x\implies \cfrac{540}{-10}=x \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill -54=x~\hfill](https://tex.z-dn.net/?f=%5Cbf%20%5Cbegin%7Barray%7D%7Bccll%7D%20degrees%26radians%5C%5C%20%5Ccline%7B1-2%7D%20180%26%5Cpi%20%5C%5C%5C%5C%20x%26-%5Cfrac%7B3%5Cpi%20%7D%7B10%7D%20%5Cend%7Barray%7D%5Cimplies%20%5Ccfrac%7B180%7D%7Bx%7D%3D%5Ccfrac%7B%5Cpi%20%7D%7B~~-%5Cfrac%7B3%5Cpi%20%7D%7B10%7D~~%7D%5Cimplies%20%5Ccfrac%7B180%7D%7Bx%7D%3D%5Ccfrac%7B%5Cfrac%7B%5Cpi%7D%7B1%7D%20%7D%7B~~-%5Cfrac%7B3%5Cpi%20%7D%7B10%7D~~%7D%20%5C%5C%5C%5C%5C%5C%20%5Ccfrac%7B180%7D%7Bx%7D%3D%5Ccfrac%7B%5Cpi%20%7D%7B1%7D%5Ccdot%20%5Ccfrac%7B10%7D%7B-3%5Cpi%20%7D%5Cimplies%20%5Ccfrac%7B180%7D%7Bx%7D%3D-%5Ccfrac%7B10%7D%7B3%7D%5Cimplies%20540%3D-10x%5Cimplies%20%5Ccfrac%7B540%7D%7B-10%7D%3Dx%20%5C%5C%5C%5C%5B-0.35em%5D%20%5Crule%7B34em%7D%7B0.25pt%7D%5C%5C%5C%5C%20~%5Chfill%20-54%3Dx~%5Chfill)
I honestly have no clue i just need to answer a question do i can ask my question that i needed help with,