Elementary Technical Mathematics

Published by Brooks Cole
ISBN 10: 1285199197
ISBN 13: 978-1-28519-919-1

Chapter 11 - Section 11.3 - Applications Involving Quadratic Equations - Exercise - Page 370: 5

Answer

Length = $35$ ft Width = $5$ ft

Work Step by Step

First, we can say that the width of the wing is represented by $x$, and the length can then be expressed as $(x+30)$ ft as it is $30$ ft longer than the width. So, now we know that: Length = $(x+30)$ ft Width = $x$ ft Area = $175 ft^2$ We also know that the formula for the area of a rectangle is Length × Width. Using this formula, we can substitute the values mentioned earlier to form a quadratic equation. Area = Length × Width $175=(x+30)×x$ $175=x^2+30x$ (Subtract 175 from each side to make the equation=0) $x^2+30x−175=0$ Now that we have our equation, we can solve it by factoring! $x^2+30x−175=0$ $x^2+35x-5x−175=0$ $x(x+35)-5(x+35)=0$ $(x-5)(x+35)=0$ We can make each bracket = 0 to find the solutions for $x$. $(x-5)=0$ or $(x+35)=0$ $x=5$ or $x=-35$ Since we are finding the width of a rectangle, it cannot be negative as the width cannot be below 0. So, $x=5$. Length = $(5)+30$ = $35$ ft Width = $5$ ft
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