I’m late on hw and need it done now or I repeat grade

Does the point (1, sqrt 7) lie on circle shown.

Line segment eg is partitioned by point f in the ratio 1: 1. point e is at e (0, 4), and point f is at (1, 3). what are the coordinates of point g? (−1, 5) (2, 2) (3, 1) (4, 0)

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.