Answer
$3x + 7y = 63$
All combinations of field goals (x) and touchdowns with extra points (y):
(0, 9), (7, 6), (14, 3), (21, 0)
Work Step by Step
field goals are 3 points, touchdowns with extra points are 7 points, home team scored 63 points
$3x + 7y = 63$