Study guides that actually teach
In-depth, free explainers on the subjects and exams you're tackling — then study them with the full AI Matrx toolkit.
Study guides & explainers
Clear, comprehensive content on the topics you're studying — free to read, easy to turn into flashcards, quizzes, and audio.
GRE Verbal: The Complete Strategy Guide
The three GRE Verbal question types, the reasoning strategies that beat trap answers, and a vocabulary plan that sticks — with free certified decks.
AP Biology: The Big Ideas, Explained
The four Big Ideas and eight units of AP Biology, how the exam scores reasoning over recall, and a plan to master both content and science practices — with free certified decks.
SAT Math: The Complete Study Guide
How the digital SAT Math section is built, the four content domains it tests, and a proven plan to raise your score — with free certified practice decks.
Cell Structure and Function, Explained
A clear walkthrough of the cell — the basic unit of life — covering the major organelles, the difference between prokaryotic and eukaryotic cells, and how structure drives function.
Supply and Demand, Explained
How prices are set in a market — the law of demand, the law of supply, how they meet at equilibrium, and what makes the whole curve shift — the single most important model in economics.
Newton's Three Laws of Motion, Explained
The three laws that govern how objects move — inertia, force equals mass times acceleration, and action-reaction — with the intuition, the equations, and the everyday examples that make them stick.
Solving Linear Equations, Explained
A step-by-step guide to solving for an unknown in a linear equation — isolating the variable, balancing both sides, clearing fractions, and checking your answer — the foundation of all of algebra.
The French Revolution: Causes and Timeline
Why France's old order collapsed after 1789 — the financial crisis, social inequality, and Enlightenment ideas that lit the fuse — and a clear timeline from the Estates-General through the Terror to Napoleon.
The Cell Cycle and Mitosis, Explained
How a single cell becomes two identical daughter cells — the phases of the cell cycle, the stages of mitosis, the checkpoints that keep division under control, and why failures lead to cancer.
AP World History: The Complete Study Guide
What AP World History covers, how the exam is structured, the nine units and their themes, and the fastest way to master it — from the 1200 CE starting point to the modern era.
Photosynthesis, Explained
How plants, algae, and some bacteria turn sunlight, water, and carbon dioxide into sugar and oxygen — the light-dependent reactions, the Calvin cycle, and why this single process underwrites nearly all life on Earth.