What number is in the tenths place in 12.75

Acircle has a radius of 5/6 units and is centered at (3.6, 7.8) write the equation of this circle

If f(x)=-x^2+6x-1 and g(x)=3x^2-4x-1,find(f+g)(x)

The serenity and the mystic are sail boats. the serenity and the mystic start at the same point and travel away from each other in opposite directions. the serenity travels at 16 mph and the mystic travels at 19 mph. how far apart will they be in 3 hours?