FeaturesHow It WorksFor ParentsPricingContactLog inStart free — no credit card needed →

Specialist Mathematics · Unit 3 · Further complex numbers · Factorisation of polynomials

Apply the factor theorem and the remainder theorem for polynomials.

Practise this objective

AI-marked practice questions tied to QCAA mark schemes for this exact LO. Free to start.

Start free practice

Practice questions for this objective

Full questions, answers and worked solutions unlock when you start a free practice session.

Question 1

Given \(P(z) = z^3 + (2 - i)z^2 + az + b\), where \(a, b \in \mathbb{C}\), the polynomial has \((z - (1 + i))\) as a factor. Additionally, when \(P(z)\) is divided by \((z + 2)\), the remainder is \(6 + 2i\). (a) Use the factor theorem to find the value of \(a\). (2 marks) (b) Use the remainder theorem to find the value of \(b\). (2 marks)

Worked answer
🔒 Start free to see full answer
Question 2

Given that \(P(z) = z^3 + (2-i)z^2 - 4z + k\), where \(k \in \mathbb{C}\), has a remainder of \(5 + 3i\) when divided by \(z + 1\), apply the remainder theorem to determine the value of \(k\).

Worked answer
🔒 Start free to see full answer
Question 3

Given that \( P(z) = z^3 + (2 - i)z^2 + az + b \) and \( Q(z) = z^2 - 3iz + c \), where \( a, b, c \in \mathbb{C} \), have the same remainder when divided by \( z + i \), and \( (z - 2i) \) is a factor of \( P(z) \), determine the values of \( a \) and \( b \).

Worked answer
🔒 Start free to see full answer
Question 4

The polynomial \(P(z) = z^3 + 2iz^2 + kz + 9i\), where \(k \in \mathbb{C}\), has a factor of \((z + 3i)\). Use the factor theorem to determine the value of \(k\).

Worked answer
🔒 Start free to see full answer
Unlock all 4 answers — free

More in Factorisation of polynomials

Next →
Solve polynomial equations over ℂ to order 4 including those with real and imaginary coefficients, e.g. solve 𝑧4 + 𝑧3 − 𝑧2 + 𝑧 − 2 = 0 and 𝑧3 − 2𝑖 𝑧2 + 𝑧 − 2𝑖 = 0.
All LOs in Factorisation of polynomialsBack to full Specialist Mathematics syllabus