What’s the correct answer?

Which representation has a constant of variation of -2.5

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

The circle below is centered at the point (3, 1) and has a radius of length 2. what is the equation?