Question

A bookmark has an area of 14 square centimeters and a perimeter of 18 centimeters. What are the dimensions of the bookmark?

Answer 1

Answer:

2 x 7

Step-by-step explanation:

a * b = 14

2a + 2b = 18

(a * b)/b  = 14/b Dividing both sides by b

a = 14/b

Substitute a in the perimeter equation

2(14/b) + 2b = 18

28/b + 2b = 18

2b - 18 + 28/b = 0

Multiply both sides by b

2b^2 - 18b + 28 = 0

Divide both sides by two

b^2 - 9b + 14 = 0

The Factors of 14 include -2 and -7 which add up to -9

(b - 2) * (b - 7) = 0

This has two answers because b can be either the side that is 2 long or 7 long, so there's no need to go back and solve for a.

2 x 7