A line passes through #(2 ,8 )# and #( 3, 5 )#. A second line passes through #( 4, 4 )#. What is one other point that the second line may pass through if it is parallel to the first line?

1 Answer
Jul 15, 2016

One possible point would be #(6,-2)#

Explanation:

A line through #(2,8)# and #(3,5)# has a slope of
#color(white)("XXX")(Deltay)/(Deltax)=(5-8)/(3-2)=(-3)/1#

Any line parallel to this will have the same slope.

Any point on a line through #(4,4)# with the form
#color(white)("XXX")(4+k * Deltax,color(white)("XX")4+k * Deltay)#
with a non-zero constant #k# and #Deltax=1, Deltay=-3#
will have a slope of
#color(white)("XXX")(k * Deltay)/(k * Deltax)=(k * (-3))/(k *1)=(-3)/1#
and will therefore be parallel to the line through #(2,8)# and #(3,5)#

Arbitrarily picking #k=2#, one such point would be
#color(white)("XXX")(4+2 * Deltax,color(white)("XX")4+2 * Deltay)#
#color(white)("XXXXXX") = (4+2 * 1,color(white)("X")4+2 * (-3))#
#color(white)("XXXXXX")=(6, -2)#