If sin theta = 2/7 and tan theta> 0 what is the value of cos theta

Create a real-life situation and create a system and show how it might be modeled algebraically with a system of equations (or inequalities) show all work include a few sentences explaining the situation, your variables of choice and what each represents, and how you would set it up and solve it algebraically. !

Asap 25 pts brainliest to right best/answer

If f(x)=2x-6 and g(x)=3x+9, find (f-g)(x)