Paper 1 · Algebra
⏱ Tested in 1 exam question since 2017
Lesson 12 of 23
Algebra 12 – Nature of cubic roots
You’ll learn
- Tell apart the three root scenarios: 3 distinct, 3 with 2 equal, 1 real + 2 imaginary
- Prove a cubic has only one real root by finding it, then testing b² − 4ac
- Reduce a cubic to its quotient quadratic via trial and error + long division
Formula used
Roots of the quadratic equation
x = (-b ± √(b² − 4ac)) / 2a
On page 20 of the log tables — read it off, don’t memorise.Most recent exam questions
- 2017 P1 Q5(c)
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