How many combinations with 3 numbers 0-6?

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

Which values of p and q result in an equation with exactly one solution? px-43=-42x+q choose all answers that apply: a) p=-43 and q=-43 b) p=42 and q=43 c) p=43 and q=−42 d) p=42 and q=42

Is ofat (-25, 0), (25, 0) co- (0, -15), (0, 15)?