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Section 1.2

Algebra

Evaluating expressions, transposing formulae, indices, simultaneous and quadratic equations, number systems.

Simulation

Straight-Line Graphs & Simultaneous Equations

Straight-Line Graphs & Simultaneous EquationsFull screen ↗
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Simulation

Quadratic Equations & the Parabola

Quadratic Equations & the ParabolaFull screen ↗
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Simulation

Logarithms & Log Scales

Logarithms & Log ScalesFull screen ↗
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Notes

Algebra, summary notes

Main ideas
  • Transposing (rearranging) a formula isolates the quantity you need. Whatever operation you apply to one side, apply to the other, that is the whole rule.
  • Laws of indices let you combine powers without expanding them. A negative index means a reciprocal; a fractional index means a root.
  • Simultaneous equations solve for two unknowns from two equations, by substitution or by elimination.
  • A quadratic equation contains a squared term and generally has two solutions; the quadratic formula solves any of them.
  • Logarithms convert multiplication into addition and are the basis of decibel and other logarithmic scales used in avionics.
  • Binary and hexadecimal are the number systems behind digital aircraft systems, see Module 5 for their full treatment.
Key formulas
Laws of indices
aᵐ × aⁿ = aᵐ⁺ⁿ, aᵐ ÷ aⁿ = aᵐ⁻ⁿ, (aᵐ)ⁿ = aᵐⁿ
Negative & fractional index
a⁻ⁿ = 1 / aⁿ, a^(1/2) = √a, a⁰ = 1
Quadratic formula
x = [−b ± √(b² − 4ac)] / 2a
Log laws
log(ab) = log a + log b, log(a/b) = log a − log b, log(aⁿ) = n log a
Solved examples
  1. Transpose V = IR to make R the subject.

    Divide both sides by I: R = V / I. This is the form used whenever a resistance is calculated from a measured voltage and current.

  2. Simplify (2x³)(3x⁴).

    Multiply the coefficients and add the indices: 2 × 3 = 6 and x³⁺⁴ = x⁷, giving 6x⁷.

  3. Solve x² − 5x + 6 = 0.

    Factorising: (x − 2)(x − 3) = 0, so x = 2 or x = 3. Check with the formula: b² − 4ac = 25 − 24 = 1, x = (5 ± 1)/2 = 3 or 2. ✓

Mind map

Algebra concept map

Algebra

Quiz

Algebra quiz

Algebra

Ref 1.215 of 50Pass 75%
  1. 1. Simplify 3a + 2b − a + 4b.

    2a + 6b
    4a + 6b
    2a + 2b
  2. 2. Simplify 2(x + 3) + 3(x − 1).

    5x + 3
    5x − 3
    5x + 9
  3. 3. Simplify 4x² + 3x².

    7x²
    7x⁴
    12x²
  4. 4. Factorise 6x + 9.

    3(2x + 3)
    3(2x + 9)
    6(x + 3)
  5. 5. Factorise x² + 5x.

    x(x + 5)
    x(x + 5x)
    x²(1 + 5)
  6. 6. Simplify x³ × x⁴.

    x⁷
    x¹²
  7. 7. Simplify x⁵ ÷ x².

    x⁷
  8. 8. Simplify (x²)³.

    x⁶
    x⁵
    x⁸
  9. 9. What is x⁰ (for non-zero x)?

    1
    0
    x
  10. 10. Write x⁻¹ without a negative index.

    1/x
    −x
    x
  11. 11. Evaluate 2³ × 2².

    32
    64
    16
  12. 12. The index form x^(1/2) means:

    √x
    1/x
  13. 13. Simplify (2x²)³.

    8x⁶
    6x⁵
    2x⁶
  14. 14. Solve 2x + 5 = 17.

    6
    11
    22
  15. 15. Solve 3x − 4 = 11.

    5
    7
    45