Every distinction begins with one topic at a time.- start now
| Law | Rule | Quick example |
|---|---|---|
| Product | am × an = am+n | x3 × x4 = x7 |
| Quotient | am ÷ an = am−n | x7 ÷ x2 = x5 |
| Power of a power | (am)n = amn | (x2)3 = x6 |
| Power of a product | (ab)n = anbn | (2x)3 = 8x3 |
| Zero exponent | a0 = 1 (a ≠ 0) | (5y)0 = 1 |
| Negative exponent | a−n = 1 ÷ an | 2−3 = 1⁄8 |
| Rational exponent | am/n = n√(am) | 82/3 = 4 |
Surd facts: √(ab) = √a × √b and √(a÷b) = √a ÷ √b
To rationalise a single surd, multiply top and bottom by that surd. To rationalise a binomial denominator, multiply top and bottom by its conjugate, then use the difference of two squares.
Cubes: a3 + b3 = (a + b)(a2 − ab + b2) and a3 − b3 = (a − b)(a2 + ab + b2)
Q: Simplify (5x+1 + 5x+2) ÷ (6 × 5x). (Invented for practice.)
Split each power: 5x+1 = 5 × 5x and 5x+2 = 25 × 5x
Numerator = 5 × 5x + 25 × 5x = 5x(5 + 25) = 30 × 5x
Expression = (30 × 5x) ÷ (6 × 5x) = 30 ÷ 6 = 5
∴ the expression simplifies to 5
Q: Evaluate 82/3 + 161/2 − 251/2. (Invented for practice.)
82/3 = (3√8)2 = 22 = 4
161/2 = √16 = 4
251/2 = √25 = 5
4 + 4 − 5 = 3
∴ the value is 3
Q: Rationalise the denominator of 3 ÷ (√5 − √2). (Invented for practice.)
Multiply top and bottom by the conjugate (√5 + √2):
= 3(√5 + √2) ÷ [(√5 − √2)(√5 + √2)]
Denominator (difference of two squares) = (√5)2 − (√2)2 = 5 − 2 = 3
= 3(√5 + √2) ÷ 3 = √5 + √2
∴ the simplified form is √5 + √2
Q: Simplify √48 − √27 + √12, and factorise 8x3 − 27. (Invented for practice.)
√48 = √(16 × 3) = 4√3 ; √27 = √(9 × 3) = 3√3 ; √12 = √(4 × 3) = 2√3
4√3 − 3√3 + 2√3 = 3√3
8x3 − 27 is a difference of two cubes with a = 2x, b = 3:
= (2x − 3)((2x)2 + (2x)(3) + 32) = (2x − 3)(4x2 + 6x + 9)
∴ √48 − √27 + √12 = 3√3, and 8x3 − 27 = (2x − 3)(4x2 + 6x + 9)
Algebra rewards the patient: take the base apart, and the rule that was hiding inside shows itself.- on simplifying
Powers add across multiplication and subtract across division, but never combine across a plus or minus. A fractional power is a root: am/n is the nth root of am. Simplify a surd by pulling out its largest perfect-square factor, and clear a surd from a denominator by multiplying by the conjugate. Factorise fully by trying common factor, difference of two squares, trinomials and, new this year, the sum and difference of two cubes.
This is a free preview of Topic 1. The full guide has every topic, the self-marking quizzes, mock exams, planner, journal and wellbeing tools.
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Exam stress is completely normal. Here are a few things that actually work. None of this replaces a doctor or a trusted adult.
Box breathing: 4 counts in, 4 hold, 4 out, 4 hold. Do it four times.
Look at the worked example below first, then make your own. Tick off each topic as you finish it.
Example (already filled in)
| Date | Subject | Topic | Done |
|---|---|---|---|
| Mon 8 Jul | Mathematics | Your weakest topic, notes + summary | ✓ |
| Tue 9 Jul | Mathematics | Next topic + 10 practice questions | ✓ |
| Wed 10 Jul | Mathematics | A full past paper under time | – |
| Thu 11 Jul | Mathematics | Mark the paper, revise weak spots | – |
Your plan
| Date | Subject | Topic | Done |
|---|---|---|---|
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A winner is a loser who tried one more time.- keep going, all the way to the exam