PAss Functional Skills

Quadratic expressions

Quadratic expressions for A Level Statistics OCR Higher: what it means, how to set the working out, and the questions it is asked in.
  • A Level
  • OCR
  • Statistics
  • Higher
  • Spec P6
  • 14 min read
  • 10 revision boxes

Introduction

2 boxes
4 min read

What is quadratic expressions?

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Transcript

A short spoken summary of quadratic expressions and where it is used.

A spoken walk-through of quadratic expressions before you read the notes.
Read the units in the question before you start; a converted unit is the most common slip.
Worth knowing: a2+b2=c2a^2 + b^2 = c^2.
2 rows

The quadratic expressions reference table

The specification wording is precise here, and the mark scheme follows that wording exactly.
Term
Meaning
Example
Common slip
Row 1 column 1
Row 1 column 2
≈160\approx 160
Row 1 column 4
Row 2 column 1
Row 2 column 2
49=7\sqrt{49} = 7
Row 2 column 4

Learning

6 boxes
5 steps

How to work with quadratic expressions

Work through the method one line at a time and write down what changes at each step.
Worth knowing: a2+b2=c2a^2 + b^2 = c^2.
  1. Read the question and write down what is being asked for.
  2. Set out the working for quadratic expressions in the order the method gives.
  3. Substitute the values and simplify.
  4. Check the answer against an estimate before writing it down.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: 34×25\frac{3}{4} \times \frac{2}{5}.
Answer: 49=7\sqrt{49} = 7
2 rules

Key facts: Quadratic expressions

Check the answer against an estimate before you move on, so a place-value slip is caught here.
The layout below is the one the mark scheme expects.

Diagram showing quadratic expressions laid out step by step

The same idea drawn out, so the method is visible.

  • Rule 1

    How quadratic expressions behaves in the 1st of the cases the specification names.
    ≈160\approx 160

  • Rule 2

    How quadratic expressions behaves in the 2nd of the cases the specification names.
    x2+5x+6=0x^2 + 5x + 6 = 0
5 steps

How to work with quadratic expressions

Read the units in the question before you start; a converted unit is the most common slip.
Worth knowing: 34×25\frac{3}{4} \times \frac{2}{5}.
  1. Read the question and write down what is being asked for.
  2. Set out the working for quadratic expressions in the order the method gives.
  3. Substitute the values and simplify.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: ×10\times 10 moves every digit one column left.
Answer: 49=7\sqrt{49} = 7
3 rules

Key facts: Quadratic expressions

The specification wording is precise here, and the mark scheme follows that wording exactly.

  • Rule 1

    How quadratic expressions behaves in the 1st of the cases the specification names.
    ≈160\approx 160

  • Rule 2

    How quadratic expressions behaves in the 2nd of the cases the specification names.
    a2+b2=c2a^2 + b^2 = c^2
4 steps

How to work with quadratic expressions

Work through the method one line at a time and write down what changes at each step.
The layout below is the one the mark scheme expects.

Diagram showing quadratic expressions laid out step by step

The same idea drawn out, so the method is visible.
  1. Read the question and write down what is being asked for.
  2. Set out the working for quadratic expressions in the order the method gives.
  3. Substitute the values and simplify.
Start from the definition and substitute the numbers the question gives you.
Simplify one line at a time: 49=7\sqrt{49} = 7.
Answer: ≈160\approx 160
2 rules

Key facts: Quadratic expressions

Check the answer against an estimate before you move on, so a place-value slip is caught here.
Worth knowing: x2+5x+6=0x^2 + 5x + 6 = 0.

  • Rule 1

    How quadratic expressions behaves in the 1st of the cases the specification names.
    49=7\sqrt{49} = 7

  • Rule 2

    How quadratic expressions behaves in the 2nd of the cases the specification names.
    x2+5x+6=0x^2 + 5x + 6 = 0

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Examples

2 boxes
4 marks · worked

Worked example: quadratic expressions

Work through the method one line at a time and write down what changes at each step.
The layout below is the one the mark scheme expects.

Diagram showing quadratic expressions laid out step by step

The same idea drawn out, so the method is visible.
Worth knowing: ×10\times 10 moves every digit one column left.
3 marks · worked

Practice question 10: a2+b2=c2a^2 + b^2 = c^2

The examiner marks the working, so a correct answer with no method still drops marks.
Worth knowing: a2+b2=c2a^2 + b^2 = c^2.

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Common questions

How many marks is quadratic expressions usually worth?
Between one and four, depending on how many steps the question asks for.
Is this on the A Level Statistics OCR Higher paper?
Yes — it sits in the Transformations strand.