In triangles abc and lmn, ∠a ≅ ∠l, ∠b ≅ ∠m, and ∠c ≅ ∠n. is this information sufficient to prove triangles abc and lmn congruent through asa? explain your answer.

Aclassmate thinks that solving a system by graphing gives an exact answer when the lines appear to cross at a grid point, but only an approximate answer when they don't. explain why this isn't true.