How do you write this equasion in slope intercept form? Points (3, -5) and is perpendicular to y=1/8x+3.

The given slope is 1/8. A perpendicular line has a slope, m, that is the negative reciprocal of that. What is the negative reciprocal of 1/8?

You are given a point it passes through, x=3 and y=-5

Plug all that into y=mx+b and solve for b. There you have it.

See. If a line is perpendicular to another line, then it is at a 90 degree angle to that line. Therefore, it's slope is the complete opposite.

See why the slope is the negative reciprocal now?

Just a slight thing I'd like to point out. The gradient of the perpendicular line is not always the negative reciprocal but the opposite sign reciprocal.

If it were -1/2, the gradient of the perpendicular line would be 2

The last time I checked, the negative reciprocal of -1/2 is +2 :-)

I won't like to give you a reddie, but the reciprocal of -1/2 is -2!!

The negative reciprocal is the negative of the reciprocal. It's not always 'negative' in and of itself.

The sign is for the whole thing and not for the 'reciprocal'. Like

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The slope of a line perp. To a line with slope 1/8 is -8.

The negative reciprocal of -1/2 is 2.

And so on.

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Originally Posted by Perito

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Yes, like I said.