In standard form the two equations are
7x +y = 5
7x +y = -5
The equations describe lines that are parallel.
The circumference = 2×pi×radius
the small = 2×3.14×4 = 25.12 inches
the medium = 2×3.14×5 = 31.4 inches
the large = 2×3.14×6 = 37.68 inches
4(3-7x). Since there are 4 sides in a square, you multiply one length by 4 to get the perimeter. 4(3-7x) simplifys to 12-28x.
9.82-9.71=.11
.11x100 divided by 9.82 = 1.12%