Level 2 Algebra Walkthrough
2025 NCEA Level 2 Algebra Question 1(c)
2025 Paper
Question
One of the x-intercepts is \((1.5,0)\), and the point \((-1,-5)\) lies on the graph.
Find the values of \(a\) and \(b\).
First walkthrough idea
Hint to try first
Use the known root \(x=1.5\) to write the quadratic in factorised form.
Step 1
Build the factorised form
That gives a factor of \((x-1.5)\) and still expands to a quadratic with leading term \(2x^2\).
Show the first step’s working
That gives a factor of \((x-1.5)\) and still expands to a quadratic with leading term \(2x^2\).
Key result
\[ (2x-c)(x-1.5) \]Walkthrough overview
What this question practises
This 2025 walkthrough is part of AS91261 — Apply algebraic methods in solving problems.
Method: Building a quadratic from a root and a point on the graph.
This is Question 1(c) from the 2025 NCEA Level 2 Algebra paper for AS91261 — Apply algebraic methods in solving problems. Use the guided hints to practise the method before revealing the full working.
Calc.nz is an independent learning resource. Compare questions, diagrams, and assessment information with the official NZQA resources for AS91261.
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Learning summary
Review the method, not only the answer
This walkthrough helps you practise building a quadratic from a root and a point on the graph. Use the hints to plan the method, then repeat the question without hints and check each step.
Common mistake to avoid
Check each step against the original condition, preserve signs and restrictions, and confirm that the final result answers the question asked.