Mathematics · Foundation

Algebra Essentials

Algebra is the language for describing relationships between quantities. If arithmetic is about specific numbers, algebra is about patterns that hold for any number. This course builds it up carefully: what a variable is, how to solve equations by keeping them balanced, how straight lines encode rates of change, how to turn a sentence into an equation, and how to handle two unknowns at once. It deliberately stops short of quadratics, factoring and exponents, and points you at OpenStax for those.

What you'll learn

• Say what a letter in an equation stands for, and evaluate an expression for a given value
• Read the equals sign as a claim about two sides being the same size, and keep an equation true
• Solve a linear equation step by step, justify each move, and check the answer by substitution
• Read a straight line for its starting value and its rate, in the situation's own units
• Turn a described relationship into an equation, and test the translation with numbers
• Solve two equations at once by substitution and by elimination