A rectangular banner for a school science fair is 5 cm longer than twice its width, and it covers 168 cm². Taking the width as x cm gives 2x² + 5x − 168 = 0. Find the width of the banner.

Question

Accepted Answer

8 cm. x = -5 ± √25 + 13444 = -5 ± 37/4 = 8 or −10.5. A width must be positive, so the width is 8 cm (and the length is 2 × 8 + 5 = 21 cm, giving 8 × 21 = 168 cm²). Reporting 21 answers the wrong quantity, and 10.5 is the size of the rejected negative root.

A rectangular banner for a school science fair is 5 cm longer than twice its width, and it covers $168 cm^{2}$ .
Taking the width as $x$ cm gives $2 x^{2} + 5 x - 168 = 0$ .
Find the width of the banner.

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 The Quadratic Formula practice

A rectangular banner for a school science fair is 5 cm longer than twice its width, and it covers 168cm2.Taking the width as x cm gives 2x2+5x−168=0.Find the width of the banner.

Step-by-Step Solution

Master this chapter in 30 minutes a day.

More Class 10 The Quadratic Formula practice

A rectangular banner for a school science fair is 5 cm longer than twice its width, and it covers $168 cm^{2}$ .
Taking the width as $x$ cm gives $2 x^{2} + 5 x - 168 = 0$ .
Find the width of the banner.