For now I don't know the answer to this problem of yours.
The samples he chose may not be a representative sample because the number of students per foreign language class may not be the same. One class may have a very large number of students while another may have only a few. Taking equal number of students per class is not a representative sample.<span />
Answer:
x=4y-6
Step-by-step explanation:
4y - x = 6
x=4y-6
To prove:
where
Using trigonometry formula:
Taking Left hand side
Hence proved