A coefficient is the number multiplying a variable in a term. In 5x the coefficient is 5; in −3y it is −3 (the sign is part of it). A variable written alone, like x, has an understood coefficient of 1, and −x has coefficient −1. Coefficients tell you "how many" of the variable you have, which is exactly what you add or subtract when combining like terms. Reading coefficients accurately — including hidden 1s and negative signs — prevents the most common simplification errors on the SAT.
✅ Solved examples
1. What is the coefficient of x in 7x?
The number multiplying x is 7.
2. What is the coefficient of y in −4y?
Including the sign, it is −4.
3. What is the coefficient of x in x?
A lone variable has an understood coefficient of 1.
4. What is the coefficient of x² in 6x²?
The coefficient is 6.
✏️ Practice — try these, take hints as needed
1. What is the coefficient of x in 9x?
The number multiplying x.
It is 9.
—
9.
2. What is the coefficient of a in −7a?
Include the sign.
−7.
—
−7.
3. What is the coefficient of x in −x?
A lone variable has coefficient 1.
With the minus, it is −1.
—
−1.
4. What is the coefficient of y² in 12y²?
Number multiplying y².
12.
—
12.
5. In the term (2/3)x, what is the coefficient?
The number multiplying x.
It is the fraction.
2/3.
2/3.
📝 Topic test — 8 questions
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substitute values, then simplify (order of operations)
Digital SAT reference
Area & Circumference
Circle area
A = πr²
Circle circumference
C = 2πr
Rectangle
A = ℓw
Triangle
A = ½ b h
Volume
Rectangular box
V = ℓwh
Cylinder
V = πr²h
Sphere
V = 4⁄3 πr³
Cone
V = 1⁄3 πr²h
Pyramid
V = 1⁄3 ℓwh
Right triangles
Pythagorean theorem
a² + b² = c²
30°–60°–90°
sides x : x√3 : 2x
45°–45°–90°
sides s : s : s√2
Constants
Degrees in a circle
360°
Radians in a circle
2π
Angles of a triangle
sum = 180°
🖩 Graphing Calculator
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