If y varies directly as x, and y is 12 when x is 1.2, what is the constant of variation for this relation?

How do you do this geometry problem

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

Florence price's brownies and more sells all types of cookies and pastries. on tuesdays, they markdown all brownies 75% to a sale of $1.50 a dozen. find the selling price and the markdown of a dozen brownies.