Question 445906
Write an equation of the line containing the given point and perpendicular to the given line. Express your answer in the for form of y=mx +b
(6,7); 3x + y=8
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The given line has slope-intercept form y = -3x+8
So it's slope is -3.
The equation you want must have slope 1/3 if it is going to a perpendicular line.
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So find the equation of a line with slope 1/3 passing thru (6,7)
y = mx + b
7 = (1/3)6 + b
21/3 = 6/3 + b
b = 15/3 = 5
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Equation:
y = (1/3)x+5
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Find the slope, if it exists, of the line containing the pairs of points.
(-17.7,13.5)and (-17.5, 8.7)
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Slope = (8.7-13.5)/(-17.5--17.5) 
Since the denominator is zero the slope is "undefined".
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If you plot the two points and draw a line thru them
you will see the line is vertical and passes thru
all points where x = -17.5.
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Cheers,
Stan H.
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