Kendra F. answered • 07/20/17

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A line (y=mx+b) that is perpendicular to the given line (8y-16=5x) will have a

**slope that's reversed**.If the slope of the given line is "m" then the perpendicular line will have a slope of "-1/m".

So first solve for the slope of the given line.

8y-16=5x

8y = 5x+16

y = (5/8)x + 2

The slope of the given line is 5/8

The new equation you write for the perpendicular line will have a slope of -8/5

The point (5,-5) will give you the y-intercept, b

Here's what you have so far..

y = (-8/5)x + b

plug in the point (5,-5) for (x,y) and solve for b

-5 = (-8/5)*(5) + b

-5 = -8 + b

-5 + 8 = b

3 = b

put the y-intercept into your line equation.

y = (-8/5)x + 3