How much of Algebra I is regularly usable...?

Found this list of topics taught in Algebra I:
•Representing numbers with variables
•Addition, subtraction, multiplication, and division of real numbers
•Probability and odds
•Rates, ratios, and percents
•Exponents and powers
•Order of operations
•Functions
•The distributive property
•Linear equations
•Formulas and functions
•Quadratic equations and functions
•Polynomials and factoring
•Rational equations and functions
•Pythagorean Theorem