Question

If we are given 8sin((pi/6)(x+2))+16=20the answers are -1 and 3 because 1/2 can be pi/6 or 5pi/6. However, if y = 10 *8sin((pi/6)(x+2))=10*, what would be the steps to get the answer 5.616793 (I only found one of the answers, which is 8.3803207).