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44 votes
44 votes
Are the pair of lines y = 1/2x + 1 and y = -1/2x +2 parallel, perpendicular, or neither?

User Venergiac
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1 Answer

14 votes
14 votes

It is given that


y=(1)/(2)x+1\ldots\text{.}\mathrm{}(1)


y=-(1)/(2)x+2\ldots\text{.}(1)

The general form of the line equation is


y=mx+c\ldots\ldots(3)

Here m is the slope of the line.

Comparing equation (1) and equation (3), we get

The slope of the first line is


m_1=(1)/(2)

Comparing equation (2) and equation (3), we get

The slope of the second line is


m_2=-(1)/(2)

Here


m_1=(1)/(2)\\e-(1)/(2)=m_2

These two lines are not parallel

The perpendicular condition is


m_1=-(1)/(m_2)

Substitute values, we get


(1)/(2)=-(1)/(-(1)/(2))


(1)/(2)=-(1)/(1)*-(2)/(1)


(1)/(2)=2

This is not true.

Hence these two lines are not perpenticular.

The given pair of lines are neither parallel nor perpendicular.

User Anakic
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3.0k points