What is the value of x enter your answer in the box

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

Solve the proportion of 16/50=x/156.25

The spanish club held a car wash to make money. the equation y=5x represents the amount of money y club members made for washing x cars. identify the constant of proportionality. then explain what it represents in this situation