
Expressions and One-Variable Equations
Variables, equivalence, and balance

See the pattern, choose the form, and check the answer.
This workbook helps learners in grades 9–12 make sense of quadratics. It starts with tables and second differences, then shows how standard, factored and vertex forms each reveal a different feature of a parabola. Learners solve equations by factoring, square roots, completing the square or the quadratic formula, and check every solution. The last module uses simple stated models of area and motion and asks which answers make sense. Each module moves from a plain explanation to worked examples, guided and independent practice, and spaced review. An explanatory answer key at the back supports adults who check the work.
For learners in grades 9–12 who can solve linear equations and multiply two binomials.
Covered
- This book is about quadratics: expressions and functions of degree two, such as x² − 6x + 8.
- You will spot quadratic patterns in tables, read features of a parabola from three forms, solve quadratic equations with real solutions, and decide which answers make sense in a context.
- Pages 53–55 add completing the square and function notation f(x).
Not covered
Not in this book: complex-number solutions, quadratic inequalities, systems of equations and higher-degree polynomials.
Before you start
If lines and slope feel shaky, work through Linear Equations and Graphs first.
Things to have
- You need a pencil, an eraser and a scientific calculator for square roots.
- Graph paper helps but is not required.
Notice
Pictures in this book are simplified learning models. Check answers with the explanations at the back of the book.
Check the skills you need before you begin. If something feels tricky, an adult can help you start in the right place.
Read a short, clear explanation of the new idea and the words that go with it.
Watch the idea being used, one step at a time, in a worked example.
Practice with prompts and help cues. The help gets smaller as you get stronger.
Practice on your own with different kinds of questions, and explain your thinking.
Look back at earlier learning so it stays strong, then check where to go next.
Check your answers. Each answer explains why, names a common mistake, and shows how to fix it.