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Identify variables, coefficients, constants, and terms

An algebraic expression is composed of terms separated by addition or subtraction; within each term, a variable represents an unknown or changing quantity, a coefficient is its numerical multiplicative factor, and a constant is a value without a variable. Learners distinguish terms from their parts, including implied coefficients such as 1 in xx and signed coefficients or constants, which supports identifying like terms and simplifying expressions; advanced polynomial classification and abstract coefficient systems are beyond this scope.

Detailed Explanation: Identify variables, coefficients, constants, and terms

An algebraic expression is made of terms. Terms are separated by addition or subtraction signs. Each term may contain:

  • A variable: a letter that represents an unknown or changing number.
  • A coefficient: the number multiplied by a variable.
  • A constant: a number without a variable.

Consider the expression

3a−2b+5−c3a - 2b + 5 - c

Step 1: Identify the terms.

Separate the expression at the addition and subtraction signs. Remember that the sign belongs to the term after it:

3a−2b+5−c\boxed{3a} \quad \boxed{-2b} \quad \boxed{+5} \quad \boxed{-c}

The terms are 3a3a, −2b-2b, +5+5, and −c-c.

Step 2: Identify the variables.

The letters are the variables:

a, b, and ca,\ b,\ \text{and } c

Step 3: Identify the coefficients.

Look for the numerical factor multiplying each variable:

  • In 3a3a, the coefficient is 33.
  • In −2b-2b, the coefficient is −2-2.
  • In −c-c, the coefficient is −1-1 because −c-c means −1c-1c.

The constant term +5+5 has no variable.

Step 4: Identify the constant.

The number without a variable is

+5+5

So, for 3a−2b+5−c3a - 2b + 5 - c:

  • Terms: 3a3a, −2b-2b, +5+5, and −c-c
  • Variables: aa, bb, and cc
  • Coefficients: 33, −2-2, and −1-1
  • Constant: +5+5

A variable written by itself has an implied coefficient of 11, while a negative variable has an implied coefficient of −1-1.

Learn by doing: Identify variables, coefficients, constants, and terms

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Like Terms - Identify - Order 1 - Fractional - One Variable - Expression to Pair


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