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# HALP

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Consider the lines\begin{align*}
y&=3x+5 \\ 2y&=4x+5 \\ 3y&=9x-2 \\ 2y&=x-3 \\ 4y&=x-5.
\end{align*}Let's say that a pair of lines is ${good}$ if the two lines are either parallel or perpendicular to each other. Among all the pairs of lines shown, how many pairs are good?

Jan 30, 2021

#1
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Slope of first line =   3

Slope of second line = 4/2  = 2

Slope of third line  =  9/3  =  3

Slope of fourth line =  (1/2)

Slope of fifth line     =    (1/4)

1 pair is good        one and  three

Jan 31, 2021