Definitions [6]
An inequation is a relation showing inequality between two quantities.
Symbols used:
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> greater than
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< less than
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≥ greater than or equal to
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≤ less than or equal to
An inequation involving one variable of degree 1 is called a linear inequation in one variable.
General forms:
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ax + b > c
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ax + b < c
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ax + b
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ax + b
(where a, b, c are real numbers and a ≠ 0)
The set from which values of the variable are taken is called the
replacement set or domain.
The set of all values from the replacement set that satisfy the inequality is called the solution set.
A function f(x) is a rule or expression whose value depends on the variable x.
The value of the function at x = a is denoted by f(a) and is obtained by substituting x = a in f(x).
An expression of the form
f(x) = a₀xⁿ + a₁xⁿ⁻¹ + a₂xⁿ⁻² + … + aₙ₋₁x + aₙ,
where a₀, a₁, a₂, …, aₙ₋₁, aₙ are real numbers and a₀ ≠ 0, is called a polynomial of degree n
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Degree of a polynomial = highest power of the variable.
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Leading term: term with the highest power.
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Leading coefficient: coefficient of highest power.
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Constant term: term without the variable.
Key Points
| Operation on Both Sides | Inequality Sign | Example |
|---|---|---|
| Add the same number | No change | (x - 2 < 4 ⇒ x < 6) |
| Subtract the same number | No change | (x + 3 > 7 ⇒ x > 4) |
| × or ÷ by a positive number | No change | (x < 6 ⇒ 3x < 18) |
| × or ÷ by a negative number | Reverses | (-2x > 6 ⇒ x < -3) |
