Please help a girl out! I'm very confused

If jklm is a trapezoid, which statements must be true?

Let f(x) = 1/x^2 (a) use the definition of the derivatve to find f'(x). (b) find the equation of the tangent line at x=2

The temperature of a chemical solution is originally 21 ? c . a chemist heats the solution at a constant rate, and the temperature of the solution 75 ? c after 1212 12 minutes of heating. the temperature, tt t , of the solution in ? c is a function of x , the heating time in minutes. write the function's formula.