How do u add and subtract positive and negative fractions?

Express the following as a function of a single angle. cos(60) cos(-20) - sin(60) sin(-20)

Which is the graph of this function 3 square root of x plus one if

Grading scale 1 has the following weights- (tests- 50% quiz- 25% homework- 15% final exam- 10%). calculate your final average if your performance in the class is as follows-test grades- {88, 84, 90, 75, 70, 81); quiz grades- {88, 67, 90, 90, 45, 99, 76, 98, 100}; homework- 90; final exam- 75