Given set {1,2,3,4,5,6,7} Two number can be taken from set =49 ways. Now, for lx2+mx+1>0 m2−4l<0⇒m2<4l If l=1⇒m2<4⇒m=1 ‌l=2⇒m2<8⇒m=1,2 ‌l=3⇒m2<12⇒m=1,2,3 ‌l=4⇒m2<16⇒m=1,2,3 ‌l=5⇒m2<20⇒m=1,2,3,4 ‌l=6⇒m2<24⇒m=1,2,3,4 ‌l=7⇒m2<28⇒m=1,2,3,4,5 ‌∴‌ Required probability ‌=‌