Expressions Math Example 2

Follow the full solution, then compare it with the other examples linked below.

Example 2

medium
Evaluate 2a2−3a+12a^2 - 3a + 1 when a=3a = 3.

Solution

  1. 1
    Substitute a=3a = 3: 2(3)2−3(3)+12(3)^2 - 3(3) + 1.
  2. 2
    Compute the exponent first: 2(9)−3(3)+12(9) - 3(3) + 1.
  3. 3
    Multiply: 18−9+118 - 9 + 1.
  4. 4
    Add and subtract left to right: 18−9+1=1018 - 9 + 1 = 10.

Answer

1010
Evaluating an expression means substituting a value for the variable and computing the result using the correct order of operations: exponents first, then multiplication, then addition and subtraction.

About Expressions

A combination of numbers, variables, and operations (like addition, subtraction, multiplication, division) that represents a mathematical quantity. Unlike equations, expressions do not contain an equals sign and cannot be solved — they can only be simplified or evaluated.

Learn more about Expressions →

More Expressions Examples

Example 1 easy

Simplify the expression [formula].

Example 3 easy

Simplify [formula].

Example 4 medium

Write an algebraic expression for: 'triple a number, then subtract 4.'

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