Consider $L_1 = {a^nb^nc^md^m, m,n \ge 1}$

$L_2 = {a^nb^n, n \ge1}$ $L_3 = {(a+b)^*}

Consider $L_1 = {a^nb^nc^md^m, m,n \ge 1}$

$L_2 = {a^nb^n, n \ge1}$ $L_3 = {(a+b)^*}