Can someone please simplify this for me?

If p(a) = 0.70 and p(b) = 0.20, then a and b are independent events if

Consider the input and output values for f(x) = 2x - 3 and g(x) = 2x + 7. what is a reasonable explanation for different rules with different input values producing the same sequence?

Binh says the point of intersections is (0,-3) which statements identify the errors binh made , check all that apply