Chapter · Math

Algebra

The art of working with unknowns. Algebra introduces the symbols, equations, and structural moves that the rest of mathematics builds on — from balancing a single equation to manipulating whole families of curves.

Topics
Topic 1

Variables & Expressions

Letters as stand-ins for numbers, the syntax of expressions, and the difference between expressions and equations.

10 min read
Topic 2

Linear Equations

Equations where each unknown appears to the first power. Solving, graphing, and the three forms — slope-intercept, point-slope, standard.

10 min read · Interactive playground
Topic 3

Systems of Linear Equations

Two or more lines, one answer (or none, or infinite). Substitution, elimination, and the geometric meaning of intersection.

12 min read · Interactive playground
Topic 4

Gaussian Elimination

The algorithm that mechanizes solving systems. Augmented matrices, the three row operations, row-echelon and reduced row-echelon form — and the gateway to matrices.

12 min read
Topic 5

Inequalities

When the answer is a region, not a point. Solving linear inequalities and graphing solution sets.

10 min read
Topic 6

Functions

From "rule that maps input to output" to domain, range, composition, and inverses.

11 min read
Topic 7

Exponents & Radicals

Powers, roots, and the algebraic identities that let you move between them.

11 min read
Topic 8

Exponential & Logarithmic Functions

f(x) = a·bˣ and its inverse. Growth, decay, the natural base e, log laws, and the equations that mix them.

14 min read · Interactive playground
Topic 9

Polynomials

Adding, multiplying, and factoring expressions with multiple terms. The bridge to higher-degree equations.

11 min read
Topic 10

Factoring Techniques

The full toolbox: GCF, grouping, difference of squares, perfect-square trinomials, sum/difference of cubes, and the AC method.

12 min read
Topic 11

Quadratic Equations

Equations of degree two. Factoring, completing the square, and the quadratic formula derived from first principles.

12 min read
Topic 12

Rational Expressions

Fractions of polynomials. Domain restrictions, simplifying, common denominators, and the extraneous-solution trap.

13 min read
Topic 13

Partial Fraction Decomposition

Un-adding fractions. The four cases — distinct linear, repeated linear, irreducible quadratic — and the cover-up shortcut. The on-ramp to integration tricks in calculus.

13 min read
Topic 14

Sequences & Series

Arithmetic and geometric patterns, closed-form formulas, sigma notation, and a first encounter with infinite sums and convergence.

13 min read · Interactive playground
Topic 15

The Binomial Theorem

Pascal's triangle, binomial coefficients, and the formula that expands (a+b)ⁿ without multiplying n times. Where algebra and counting meet.

12 min read