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write the equation for the line perpendicular to y=-1/4x+9 and passing through the point (-9,9) in slope-intercept form.

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4 votes

Answer:

y = 4x + 45

Explanation:

The slope for the equation y = -1/4x + 9 would be the number before the x. In this case, that number is -1/4. A perpendicular slope would be the opposite inverse to this number which would be 4. We know have the slope. We need the y- intercept.

To find the y-intercept we would need and x and y value that is on the line and the slope. We are given this information. From above, we see that the slope is 4. We can use the x and y from the ordered pair given (-9,9) The x value is -9 and the y value is 9.

y = mx + b Substitute in what we know.

9 = 4(-9) + b We are soling for b

9 = -36 + b Add 36 to both sides of the equation

45 = b We now know the y-intercept

The equation will be:

y = mx + b

y = 4x + 45

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