Writing Equations from Context Math Example 1

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

Example 1

easy
Write an equation: 'Three times a number decreased by 4 is 17.'

Solution

  1. 1
    Let nn = the unknown number.
  2. 2
    'Three times a number' = 3n3n.
  3. 3
    'Decreased by 4' = 3n−43n - 4.
  4. 4
    'Is 17' = =17= 17. Equation: 3n−4=173n - 4 = 17.
  5. 5
    Solve: 3n=213n = 21, n=7n = 7.

Answer

3n−4=17;n=73n - 4 = 17; \quad n = 7
Translating word problems: assign a variable, convert each phrase to math, and connect with an equals sign.

About Writing Equations from Context

Translating real-world situations and word problems into algebraic equations by identifying the unknown, choosing a variable, and expressing relationships mathematically.

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More Writing Equations from Context Examples

Example 2 medium

A plumber charges [formula]30 per hour. If the bill was $170, how many hours did the job take?

Example 3 easy

Write an equation: 'Half of a number plus 6 equals 10.'

Example 4 hard

The perimeter of a rectangle is 34 cm. The length is 5 cm more than the width. Find the dimensions.

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