P(a)=0.5 p(a|b)=25 p(b|a)=0.2 find p(b) and find p(not b|not a)

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