Date: 9/3/96 at 13:10:58 From: Anonymous Subject: Parallel Lines Could you please help us students (Emma and Marie), as we are not getting anywhere on this question in our textbook. "The lines y=kx+4 and 3y=(k+3)x-5 are parallel. Find k." Can you explain how to do it, please? Many thanks. Emma and Marie.
Date: 9/3/96 at 14:2:48 From: Doctor Mike Subject: Re: graphs. You first need to get both line equations is slope-intercept form. The first one is in that form already. To get the second one in that form you divide both sides by 3, giving k+3 5 y = --- *x - --- 3 3 For the lines to be parallel the slopes have to be the same, so k must equal (k+3)/3 , and that is easily solved as k=3/2 . The two lines are y=(3/2)x + 4 and y=(3/2)x - (5/3). Each has the slope 3/2 and they intersect the y-axis at (0,4) and (0,-(5/3)) . I hope this helps. Write back if you have other questions. -Doctor Mike, The Math Forum Check out our web site! http://mathforum.org/dr.math/
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