Let X be a random variable with distribution function mx(x) defined by mx (-1) = 1/5, mx (0) = 1/5, mx (1) = 2/5, mx (2) = 1/5. (a) Let Y be the random variable defined by the equation Y = X + 3. Find the distribution function mY(y) of Y. (b) Let Z be the random variable defined by the equation Z = X^2. Find the distribution function mZ(z) of Z.