Core Practice
Workbook
20 Essential Problems — 5 Core Units
Concept Review · Worked Examples · Practice Problems · Answer Key
Variables & Expressions
A variable is a letter that represents an unknown value. An algebraic expression combines variables, numbers, and operations — but has no equal sign. To evaluate an expression, substitute the given value and calculate.
Evaluate 4x + 7 when x = 3.
4(3) + 7 = 12 + 7 = 19Solving One-Step Equations
Use inverse operations to isolate the variable. Whatever you do to one side of the equation, you must do to the other side to keep it balanced.
Solve: x + 9 = 14.
Subtract 9 from both sides → x = 5Solving Two-Step Equations
Reverse the order of operations to solve. When solving ax + b = c, first undo the addition or subtraction (dealing with b), then undo the multiplication or division (dealing with a).
Solve: 2x + 5 = 13.
2x = 8 → x = 4Inequalities
Solve inequalities just like equations, with one critical exception: when you multiply or divide both sides by a negative number, you must flip the inequality sign.
Solve: −3x < 12.
Divide by −3 and flip: x > −4Linear Equations & Slope
The slope-intercept form of a linear equation is y = mx + b, where m is the slope and b is the y-intercept. Slope tells you how steep the line is and which direction it goes.
Find the slope of the line through (1, 3) and (4, 9).
m = (9 − 3) ÷ (4 − 1) = 6 ÷ 3 = 2Answer Key & Solutions
Review every step. For any missed question, re-read the concept box and try again.