JSS2: MATHEMATICS - 2ND TERM
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Transactions in the Homes and Offices | Week 18 Topics|1 Quiz
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Expansion and Factorization of Algebraic Expressions | Week 24 Topics|1 Quiz
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Algebraic Expansion and Factorization of Algebraic Expression | Week 34 Topics|1 Quiz
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Algebraic Fractions I | Week 44 Topics|1 Quiz
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Addition and Subtraction of Algebraic Fractions | Week 52 Topics|1 Quiz
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Solving Simple Equations | Week 64 Topics|1 Quiz
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Linear Inequalities I | Week 74 Topics|1 Quiz
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Linear Inequalities II | Week 82 Topics|1 Quiz
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Quadrilaterals | Week 92 Topics|1 Quiz
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Angles in a Polygon | Week 104 Topics|1 Quiz
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The Cartesian Plane Co-ordinate System I | Week 113 Topics|1 Quiz
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The Cartesian Plane Co-ordinate System II | Week 121 Topic|1 Quiz
Word Problems Leading to Inequalities
Topic Content:
- Word Problems Leading to Inequalities
The key to word problems is translating the given information into math language. In this case, we need to translate word problems into statements of inequality.
Example 8.2.1:
If x is subtracted from 5 and the result is greater than 15. Find the range of values of x.
Solution
x subtracted from 5
5 – x
Result > 15
\( \scriptsize 5 \: – \: x > 15 \)Collect like terms
\( \scriptsize 5 \: – \: x > 15 \) \( \scriptsize -x > 15 \: – \: 5 \) \( \scriptsize -x > 10 \)Divide both sides by -1 (reverse the sign)
\( \frac {-x}{-1} < \frac{10}{-1} \) \( \scriptsize x < -10 \)Range of values of x : -11, -12, -13, …
Example 8.2.2:
Olu is x years old. In 4 years time his age will still be less than 12 years.
(a) Write this information in an inequality in x
(b) Find the maximum age of Olu to the nearest whole number
Solution
(a) In 4 years time, Olu will be (x + 4) years
x + 4 is less than 12
\( \scriptsize x \: + \: 4 < 12 \)(b) Solve \( \scriptsize x \: + \: 4 < 12 \)
collect like terms
\( \scriptsize x < 12 \: – \: 4 \) \( \scriptsize x < 8\)Range of values of x: 7, 6, 5, 4, 3, …
The maximum age of Olu is 7 years.