Lucy would save $114.
Step 1: Multiply 6.175 x 30 = 185.25
Step 2: Divide 370,000/185.25 = 1,997
Step 3: Repeat Steps 1&2 but with (6.55 x 30) and divide 370,000/196.5 = 1,883.
Step 4: Subtract 1,997 - 1,883 = 114
Step 5: She will save $114 with points versus without.
Set each piece = to 56, assuming that the 2 variables for which you are not solving are each equal to 0.
7x -2(0)-14(0) = 56
7x=56 (divide each side by 7)
X = ?
(__, 0, 0)
7(0) - 2y - 14 (0) = 56
-2y = 56 (divide each side by -2)
Y= ?
(0, __ , 0)
7(0) - 2(0) - 14z = 56
-14z = 56 (divide each side by -14)
z = ?
(0, 0, __)