Answer:
Answers is C Cos A+sin B =1
84 is 60 % of the number 140
3-√11
This function is evidently a quartic - a function with 4 roots. The last root has been found using the quadratic formula however, the answer always comes in pairs because the formula is
{b+√(b^2 - 4ac)}/2a and {b-√(b^2 - 4ac)}/2a. Therefore the other root must be 3-√11