CurriculumGrade 8Mathematics

Slope & Linear Equations (y = mx + b)

Aligned to 8.EE.B.6 — Common Core State Standards for Mathematics.

What this lesson teaches

Slope (m) is rise over run — how fast y changes as x changes. The y-intercept (b) is where the line crosses the y-axis. Together they define a line.

Worked example

Through (0, 2) and (3, 8): slope = (8−2)/(3−0) = 6/3 = 2. Intercept is 2, so y = 2x + 2.

Practice questions

  1. Find the slope between (1, 4) and (5, 12).
  2. Write the equation of a line with slope −3 through (0, 5).
  3. Graph y = (1/2)x − 1.

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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

Pendiente y Ecuaciones Lineales (y = mx + b)

La pendiente (m) es el cambio vertical entre el cambio horizontal — qué tan rápido cambia y conforme cambia x. La intersección con el eje y (b) es donde la recta cruza el eje y. Juntas definen una recta.

Ejemplo: Por los puntos (0, 2) y (3, 8): pendiente = (8−2)/(3−0) = 6/3 = 2. La intersección es 2, entonces y = 2x + 2.

More Expressions & Equations lessons

Systems 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.4Proportional Relationships & Slope8.EE.B.5

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