Answer:
c
Step-by-step explanation:
The double angle formula for the sine is

The right hand side is exactly your expression, where 
So, rewriting the expression from right to left, we have

Answer: xm + y = z xm = z - y x = (z - y)/(m)
Step-by-step explanation: hope this helped :)
The mistake she made was timesing the 6 by the -7.5 as there is no x after the 6
Therefore:
-3.8(-7.5) +6
28.5+6 =34.5