Writing the Equation of a Line Given Two Points

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​I can write the equation of a line in slope - intercept form (y = mx + b) if I am given two points.

​Slope formula

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​writing an equation given a point and a slope.

​Step 1: Start with substituting the provided information into y = mx + b.

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​Step 2: Simplify (multiply or reduce m times x)

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​Step 3: Solve for b.

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​Step 4: Write your equation.

Step 1: y = mx + b --> -4 = 2(2) + b

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​Step 2: -4 = 4 + b

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​Step 3: -8 = b

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​Step 4: y = 2x - 8

​Step 1: Use the slope formula to find the slope.

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​Step 2: Pick one of the points to use as x and y.

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​Step 3: Plug in your slope and one of the points.

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​Step 4: Solve for b.

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​Step 5: Write your equation.

​It won't matter which point you pick, you get the same answer either way.

​1. Slope formula

​2. Finding the equation of a line given a slope and a point.

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​If you're struggling with one of these, you need some practice.