Solve with quadratic formula

Question

the length of a rectangle exceeded twice its width by 3 inches. If the area is 10 square inches,.find the rectangle's dimensions. Round to the nearest tenth of an inch.

Answer 1

A = lw

l = 2w + 3

 

10 = w(2w + 3)

2w² + 3w - 10 = 10

 

w = (-b ± √4(b² - 4ac))/2a

 

w = (-3 ±√(3² - 4(2)(-10))/(2(2))

 

w = (-3 ± √(9 + 80))/4

 

w = (3 + √89)/4 = your answer for the width

 

Divide 10/w for the length

 

w = (3 - √89)/4 = not an answer, because we don't measure using negative numbers