Identifying a Quadratic Equation
A quadratic equation is any equation that can be simplified to ax^2 + bx + c = 0 with a ≠ 0.
Practice This ConceptMain explanation
Teacher explanation
Not every equation with x is quadratic. To identify a quadratic equation, first simplify it and check that the highest power of x is 2 and no higher power remains.
Example
2x(x - 3) = 8 becomes 2x^2 - 6x - 8 = 0, so it is quadratic.
Simple analogy
Degree 2 only, not degree 1 or 3.
Common confusion
Students sometimes call any equation with x a quadratic equation, even when the highest power is 1 or 3.
Exam tip
Always simplify first. The equation is quadratic only if the highest power after simplification is exactly 2.
Answer writing and exam use
1-mark use
Write the exact meaning of identifying a quadratic equation in one clean line.
2-mark use
Define identifying a quadratic equation and add one example or condition.
3-mark use
Explain identifying a quadratic equation, show the method or example, and mention the common mistake.
Practice this concept with focused MCQs
Open the concept quiz intro first, review the test details, and then start a focused MCQ set from this concept only. Instant score and answer review are live now.
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