Iforgot how to do it i wasn't at school for a couple of days

First you want to isolate X, to do that all you have to do is use the additive inverse and subtract 76 to both sides. the answer you get should be -8.5.

I'm not sure exactly but my best guess would be 1/4

Period is the time it takes for one “cycle” to complete. in the parent sine function, period is 2*pi since sin(0) = 0, sin(pi/2) = 1, sin(pi) = 0, sin(3pi/2) = -1, and sin(2pi) = 0. at that point, the sequence repeats itself. i’m not sure if your graph is similar to the sine function since you didn’t provide a picture, but you can find the period by looking at a graph.