Find the sum of ∑4/k=1 (-4k)

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

Jorge planted flowers in his garden he planted one row of 12 tulips and one row of 36 daisies george's friend kylie has a garden with 75 flowers in it kylie's garden only contains tulips and daisies. is it possible for kylie‘s garden she have the same ratio of tulips to daisies as george's garden?

Find the missing factor. write your answer inexponential form.9^2=9^4×