CurriculumGrade 8Mathematics

Solving Linear Equations

Aligned to 8.EE.C.7 — Common Core State Standards for Mathematics.

What this lesson teaches

Solve by using the distributive property, combining like terms, and getting the variable on one side. If the equation simplifies to a true statement like 5 = 5, there are infinitely many solutions; if it gives a false one like 3 = 7, there is no solution.

Worked example

Solve 3(x + 2) = 2x + 11. Distribute: 3x + 6 = 2x + 11. Subtract 2x: x + 6 = 11. Subtract 6: x = 5. This equation has one solution.

Practice questions

  1. Solve 4x − 7 = 2x + 9.
  2. Solve 2(x + 3) = 2x + 6 and describe the number of solutions.
  3. Solve 5x + 1 = 5x − 4 and describe the number of solutions.

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Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.

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En español

Resolución de Ecuaciones Lineales

Resuelve usando la propiedad distributiva, combinando términos semejantes y dejando la variable de un solo lado. Si la ecuación se reduce a una afirmación verdadera como 5 = 5, hay infinitas soluciones; si da una falsa como 3 = 7, no hay solución.

Ejemplo: Resuelve 3(x + 2) = 2x + 11. Distribuye: 3x + 6 = 2x + 11. Resta 2x: x + 6 = 11. Resta 6: x = 5. Esta ecuación tiene una solución.

More Expressions & Equations lessons

Slope & Linear Equations (y = mx + b)8.EE.B.6Systems of Linear Equations8.EE.C.8Exponents and Scientific Notation8.EE.A.1Square Roots & Cube Roots8.EE.A.2Scientific Notation & Magnitude8.EE.A.3Operations in Scientific Notation8.EE.A.4

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