document.write( "Question 203835: Write the slope-intercept equation of the line that is parallel to, -3x-5y=6 and has the same y-intercept as the graph of, 2x+y=-4 \n" ); document.write( "
Algebra.Com's Answer #153817 by PRMath(133)\"\" \"About 
You can put this solution on YOUR website!
Write the slope-intercept equation of the line that is parallel to: -3x-5y=6 and has the same y-intercept as the graph of: 2x+y=-4\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Ok, first we have to write a line that is parallel to -3x - 5y = 6. What you have to know is that parallel lines have the SAME slope. So, we just have to find the slope of this line: -3x - 5y = 6. How do we do that? Let's solve this equation for y and in doing so, we'll put the equation in slope/intercept form. The slope intercept form is y = mx + b. In this form, the \"m\" is the slope. So, let's go.......\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "First we solve for y:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "-3x - 5y = 6 (add 3x to both sides)
\n" ); document.write( "-5y = 3x + 6 (now divide both sides by -5 to isolate the y)\r
\n" ); document.write( "\n" ); document.write( "\"%28-5%29y%2F-5+=+%283x%29%2F-5+%2B+%286%29%2F-5\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "y = \"%28-3x%29%2F5+-+%286%29%2F5\"\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now can you see that your slope for the line is \"-3%2F5\"? Therefore, our next line that we create has to have this for a slope if the two lines are going to end up being parallel.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now the next part of your problem says: the line must have the same y-intercept as the graph of, 2x + y = -4. Hmmmm... What is the y intercept of this line? Here's something for you to know:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "To find the y intercept, solve for y by making x = 0.
\n" ); document.write( "To find the x intercept, solve for x by making y = 0.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "SO in our equation: 2x + y = -4
\n" ); document.write( "We just need to solve for y by making x = 0. Let's try it:\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "2x + y = -4 (original equation)
\n" ); document.write( "2(0) + y = -4
\n" ); document.write( "0 + y = -4
\n" ); document.write( "y = -4\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "SO we know that when x = 0, then y = -4. Our y intercept is -4.\r
\n" ); document.write( "
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Now what do we want? We want a line in the slope/intercept form (y = mx + b) and remember, that \"m\" is the slope. What you also have to know is that \"b\" is the y intercept. We want this new equation of a line to be parallel to the first line -3x - 5y = 6, which means the 2nd line must have (as we know from above) a slope of \"-3%2F5\".\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "SO let's plug in our info to the equation of:\r
\n" ); document.write( "\n" ); document.write( " y = mx + b
\n" ); document.write( " y = \"%28-3%29%2F%285%29\"x - 4\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Do you see how we \"plugged in\" the value for m, which was \"-3%2F5\" as well as the value for \"b\" which was -4?\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "Does that make sense for you? I hope so. :-)\r
\n" ); document.write( "\n" ); document.write( "
\n" ); document.write( "
\n" );