Variables (like x, y) represent unknown values that can change.
Constants are fixed numbers that don't change.
The goal of algebra is to find the value(s) of the variable(s).
1. Whatever you do to one side, do to the other
2. Addition and subtraction are inverse operations
3. Multiplication and division are inverse operations
4. Always check your solution by substituting back
For ax² + bx + c = 0:
x = (-b ± √(b² - 4ac)) / 2a
The discriminant (b² - 4ac) tells us:
• Positive: 2 real solutions
• Zero: 1 real solution
• Negative: No real solutions
Slope measures the rate of change:
• Positive slope: line rises left to right
• Negative slope: line falls left to right
• Zero slope: horizontal line
• Undefined slope: vertical line