Quick math help please:)

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

The graph and table shows the relationship between y, the number of words jean has typed for her essay and x, the number of minutes she has been typing on the computer. according to the line of best fit, about how many words will jean have typed when she completes 60 minutes of typing? 2,500 2,750 3,000 3,250

Using elimination, what is -4x+2y=-12 4x+8y=-24