Math · PSAT

PSAT Math Concepts

Core algebra and problem-solving concepts tuned to PSAT math section question styles, explained conceptually.

34 cards · basic cards · AI-written, checked twice. Edit anything.

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What is the slope of a line, and what does it measure?
The ratio of vertical change (rise) to horizontal change (run) between two points; measures steepness and direction of a line.
Two lines are perpendicular. If one has slope 3, what is the slope of the other?
Negative 1/3 (the negative reciprocal).
What does the y-intercept of a line represent?
The value of y when x equals zero; where the line crosses the y-axis.
Parallel lines have what relationship between their slopes?
Equal slopes.
What does the discriminant (b^2 - 4ac) tell you about a quadratic equation?
Whether the equation has two real solutions (positive), one real solution (zero), or no real solutions (negative).
What is the difference between (x + 3)^2 and x^2 + 9?
(x + 3)^2 = x^2 + 6x + 9; they are not equal. Squaring a binomial requires the middle term.
How do you factor x^2 - 16?
(x - 4)(x + 4); it is a difference of squares: a^2 - b^2 = (a - b)(a + b).
When you multiply powers with the same base, what do you do with the exponents?
Add the exponents: a^m * a^n = a^(m+n).
What does a negative exponent mean? Simplify x^(-3).
A negative exponent means take the reciprocal: x^(-3) = 1/x^3.
Simplify sqrt(72).
6*sqrt(2); factor out perfect squares: sqrt(36 * 2) = 6*sqrt(2).
What does it mean to rationalize a denominator?
Rewrite a fraction so the denominator contains no radicals, usually by multiplying by a form of 1.
What is the absolute value of -7, and what does absolute value represent?
7; absolute value is the distance from zero on a number line (always non-negative).
If you multiply both sides of an inequality by a negative number, what must you do?
Flip (reverse) the inequality sign.
Solve: |x - 2| = 5. What are the solutions?
x = 7 or x = -3; absolute value splits into two cases: x - 2 = 5 and x - 2 = -5.
What is function notation, and what does f(3) mean?
f(x) shows that the output depends on the input x; f(3) means substitute 3 for x and evaluate.

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