Solving problems involving linear equations
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This document provides two examples of solving linear equations problems. The first example finds five consecutive odd integers whose sum is 55. It sets up the linear equation and solves to find the first integer is 7. The second example is an age problem, where Margie is 3 times older than Lilet. It sets up equations to represent their current and future ages and solves to find Lilet is currently age 2 and Margie is currently age 6.
Solving problems involving linear equations
- 2. EXAMPLE # 1: NUMBER PROBLEM •Find five consecutive odd integers whose sum is 55.
- 3. SOLUTION: • Let x – be the first odd integer • x + 2 – be the 2nd odd integer • x + 4 – be the 3rd odd integer • x + 6 – be the 4th odd integer • x + 8 – be the 5th odd integer
- 4. •x + (x + 2) + (x + 4) + (x + 6) + (x + 8) = 55 •5x + 20 = 55 •5x + 20 + (– 20) = 55 – 20 •5x = 35 •x = 7
- 5. EXAMPLE #2: AGE PROBLEM •Margie is 3 times older than Lilet. In 15 years, the sum of their ages is 38 years. Find their present ages.
- 6. Age now In 15 years Lilet x x + 15 Margie 3x 3x + 15
- 7. In 15 years, the sum of their ages is 38 years. Equation: (x + 15) + (3x + 15) = 38 Solution: 4x + 30 = 38 4x = 38 – 30 4x = 8 x = 2 Answer: Lilet’s age now is 2 while, Margie’s age now is 3(2) or 6.