A line is perpendicular to another line if m2=(-1/m1), where m1 is the slope of the original line and m2 is the slope of the perpendicular line. Which of the following equations represents the line that passes through the point (1, –1) and is perpendicular to the line below?

Question

anonymous · Answer

attachment

jdoe0001 · Answer

can you find the slope of the line in the graph?

anonymous · Answer

well, i think its -3x

jdoe0001 · Answer

the slope is -3x?

jdoe0001 · Answer

do you know how to find the slope of a line?

anonymous · Answer

well, yes, but i kept getting different answers

jdoe0001 · Answer

hmmm.. different answers?.... well, the line graph has only one slope

anonymous · Answer

yeah, thats kinda part of the problem

phi · Answer

The slope in the graph is change in y  (-3) divided by change in x (1)
-3/1 = -3

(the slope is -3, not -3x)

what is the slope perpendicular to this line ?
m2=(-1/m1)

what is -1 / -3 ?

phi · Answer

@dalia_lam    that looks like the right idea,  but the slope is -3
(you can check by plugging in x=1 into the "original equation"  ... you should get y = -1
i.e. y = -3x + 2

anonymous · Answer

sorry,

anonymous · Answer

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