Find the value of x if (4/7)^-3 * (16/49)^-1 = (4/7)^n-1

Solve - pv + 40 < 65 for v solve 7w - 3r = 15 for r

Neveah and clint are baking muffins for the bake sale. they need to bake 30 muffins for their display case. clint has baked 4 so far, and neveah has baked 7. how many muffins (m) do they have left to bake? show your work!

Can someone me out here and the tell me the greatest common factor