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Application of Quadratic Equations. Word Problems Instead of giving you the question directly to solve, the problem is presented in the form of a story. Based on the story, you have to form the equation and solve it. Steps to solving a word problem.
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Application of Quadratic Equations Word Problems • Instead of giving you the question directly to solve, the problem is presented in the form of a story. • Based on the story, you have to form the equation and solve it
Steps to solving a word problem • Identify the ‘unknown’ – Let it be represented by a letter (x, y, a etc…) • Form the quadratic equation using the given information • Solve the equation • Check if your solutions satisfy the problem.
Example 1 – Ex 6.3 Q6 Identify the unknown! Form the equation! Solve! The length and breadth of a rectangle are (3x + 1) and (2x – 1) cm respectively. If the area of the rectangle is 144 cm2, find x. (rej) Are both answers acceptable?
Example 2 – Section 6.4 Eg 10 Form the equation Solve! Ans :The numbers are 16 and 18 The sum of the squares of 2 consecutivepositive even numbers is 580. Find the numbers . Identify the unknown: Let one number be x, therefore 2nd number is x + 2 (rej) Are both answers acceptable?
Try it 11 – Pg 189 x x Ans : The shorter side is 9 cm The perimeter of a rectangle is 44 cm. The area of the rectangle is 117 cm2. Find the length of the shorter side of the rectangle. Let one side be x, therefore other side is (44 − 2x) ÷ 2 = 22 – x (rej) Are both answers acceptable?
Try it 12 – Pg 189 25 + 2x 25 m 6 + 2x 6 m A rectangular swimming pool measures 25 m by 6 m. It is surrounded by a path of uniform width. If the area of the path is 102 m2, find the width of the path. Let the width be x. Therefore, length of path = 25 + 2x, breadth of path = 6 + 2x Area of pool = 25 x 6 = 150 m2 Ans: The width of the path is 1.5 m