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Algebra 1 > L6 Slope-intercept form: write an equation A421
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A line passes through the points (-4, 9) and (4, -15). Write its equation in slope-intercept
form.
Write your answer using integers, proper fractions, and improper fractions in simplest form.

User Shaish
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Final answer:

To write the equation of a line passing through two points in slope-intercept form, we need to find the slope and the y-intercept. The slope is calculated using the formula (y2 - y1) / (x2 - x1), and the y-intercept is found by substituting one of the given points into the equation. The equation of the line passing through (-4, 9) and (4, -15) is y = -3x - 3.


Step-by-step explanation:

To write the equation of a line in slope-intercept form, we need to find the slope and the y-intercept. The slope of a line passing through two points, (x1, y1) and (x2, y2), is calculated using the formula m = (y2 - y1) / (x2 - x1). Let's calculate the slope first:

m = (-15 - 9) / (4 - (-4)) = -24 / 8 = -3

Now, let's use the slope-intercept form, y = mx + b, where m is the slope and b is the y-intercept. We can substitute one of the given points into the equation to find the value of b:

9 = -3(-4) + b

9 = 12 + b

b = 9 - 12 = -3

So, the equation of the line passing through the points (-4, 9) and (4, -15) in slope-intercept form is y = -3x - 3.


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User Raffian
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