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4-14.

Solve this problem by writing and solving an equation. Be sure to define your variable. Homework Help ✎

A rectangle has a perimeter of 30 inches. Its length is one less than three times its width. What are the length and width of the rectangle?

Set up two equations:
3W − 1 = L
2W + 2L = 30

Substitute (3W − 1) for L and solve the equation:
2W + 2 (3W − 1) = 30

Width is 4 inches and length is 11 inches.