2.22.3

Solving Quadratic Inequalities

Test yourself on Solving Quadratic Inequalities

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Quadratic Inequalities

Find inequalities for x when x² > 9 and for x² < 9:

x&sup2; > 9

x² > 9

  • Square root both sides.
  • If x² is more than the answer, x must be smaller than the negative or larger than the positive.
x&sup2; < 9

x² < 9

  • Square root both sides.
  • If x² is less than the answer, x must be in between the two values.
  • A useful check is to see if x = 0 satisfies the inequality.
    • If it does x must be in between the two square roots.
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1

Number

1.1

Place Value & Ordering

1.2

Numerical Operations

1.3

Structure of Calculations

1.4

Fractions

1.5

Numerical Operations on Fractions

1.6

Roots & Powers

1.7

Numerical Skills

1.8

Factors & Multiples

1.9

Surds

1.10

Standard Form

1.11

Fractions, Decimals & Percentages

1.12

Percentage Change

1.13

Rounding & Estimation

1.14

Bounds & Accuracy

1.15

Using Numbers

1.16

Fractions, Decimals & Percentages

1.17

Powers & Roots

1.18

Accuracy

2

Algebra

2.1

Algebraic Notation

2.2

Substitution & Simplification

2.3

Brackets

2.4

Algebraic Fractions

2.5

Rearranging

2.6

Functions

2.7

Solving Linear Equations

2.8

Inequalities

2.9

Solving Quadratic Equations

2.10

Simultaneous Equations

2.11

Iteration

2.12

Sequences

2.13

Linear Graphs

2.14

Introduction to Algebra

2.15

Manipulating Algebra

2.16

Proofs & Functions

2.17

Straight Line Graphs

2.18

Common Graphs

2.19

Transformations & Tangents

2.20

Properties of Graphs

2.21

Solving Equations

2.22

Inequalities

2.23

Sequences

3

Ratio

3.1

Unit Conversions

3.2

Compound Units

3.3

Ratio Fundamentals

3.4

Advanced Ratio and Scale

3.5

Proportion

3.6

Algebraic Proportion

3.7

Ratios in Practice

3.8

Manipulating Ratios

3.9

Percentage & Interest

3.10

Proportion

3.11

Gradient

4

Geometry

4.1

Area & Perimeter

4.2

Angles

4.3

Trigonometry

4.4

Similarity & Congruence

4.5

Circle Geometry

4.6

Circle Theorems

4.7

Pythagoras

4.8

Surface Area

4.9

Volume

4.10

Vectors

4.11

Introduction to Geometry

4.12

Triangles & Quadrilaterals

4.13

Transformations

4.14

Circle Basics

4.15

Circle Theorems

4.16

Measurements & Units

4.17

Calculating Area

4.18

Triangle Formulae

4.19

3D Shapes

4.20

Vectors

5

Probability

6

Statistics

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