Please I need help with the following questions

Design PDAs that recognize the following languages. (a) L1 = {0^n1^n| n greaterthanorequalto 0} (b) L2 = (a^nb^mC^n| n, m greaterthanorequalto 0} (c) L3 = {a^nb^2n| n greaterthanorequalto 0} Show that the following languages are not context free (a) L1 = {a^nb^nc^n|n greaterthanorequalto 0} (b) L2 = {a^3k b^2k c^k elementof {a, b, c} * | k greaterthanorequalto 0} (c) L3 = {ab^kab^kab^k elementof {a, b} * | k greaterthanorequalto 0} (d) L4 = {a^k+mb^ka^mb^k elementof {a, b} * | k greaterthanorequalto 0, m greaterthanorequalto 0}