To derive the equation of the line in slope-intercept form (y = mx + b) using the points (1, 8) and (0, 4), follow these steps:
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Calculate the slope (m) using the formula: \[ m = \frac{y_2 - y_1}{x_2 - x_1} \] Let's take the points as \( (x_1, y_1) = (0, 4) \) and \( (x_2, y_2) = (1, 8) \).
Substituting the points into the formula: \[ m = \frac{8 - 4}{1 - 0} = \frac{4}{1} = 4 \]
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Use the slope-intercept form of the equation, which is \( y = mx + b \). We know \( m = 4 \), so we can write: \[ y = 4x + b \]
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Substitute one of the points to find b. You can use either point. Let's use the point (0, 4): \[ 4 = 4(0) + b \] This simplifies to: \[ b = 4 \]
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Write the final equation: \[ y = 4x + 4 \]
Thus, the equation of the line in slope-intercept form is: \[ \boxed{y = 4x + 4} \]