Oh the answer is a I looked it up this time
In the problem -5+x=0, x=5
c^2 = a^2 + b^2 - 2(ab)(cos C)
c^2 + 2(ab)(cos C) = a^2 + b^2
2(ab)(cos C) = a^2 + b^2 - c^2
cos C = (a^2 + b^2 - c^2) / 2ab - Answer choice E
Hope this helps! :)
Answer:
the answer to that is the second one, 4^-4
