A line passes through (3 ,2 )(3,2) and (1 ,3 )(1,3). A second line passes through (1 , 4 )(1,4). What is one other point that the second line may pass through if it is parallel to the first line?

1 Answer
Dec 9, 2016

One such point would be (3,3)(3,3)

Explanation:

The line, L_1L1, through (3,2)(3,2) and (1,3)(1,3) has a slope of
color(white)("XXX")m_(L1) = (Deltay_(L1))/(Deltax_(L1))=(3-2)/(1-3)=-1/2

The line, L_2, through (color(green)(1),color(magenta)4) must have the same slope if it is parallel to L_1;
that is the ratio (Deltay_(L2)):(Deltax_(L2)) must be color(red)((-1)k):color(blue)(2k)

and any point on L_2 must have the form:
color(white)("XXX")(color(green)1+color(blue)(2 * k),color(magenta)4+color(red)((-1) * k))

For an example of such a point, we could set k=1
to get the point:
color(white)("XXX")(3,3)

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