document.write( "Question 83787: HI my homework says to \" write the equation of the line in slope-intercept form:
\n" ); document.write( "parallel to -5y=10x+32 and through point P(-1,1). Can you clear things up for me? I am completley lost, and there is nothing in my textbook on this, or maybe i am just overlooking it.
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Algebra.Com's Answer #60275 by bucky(2189)\"\" \"About 
You can put this solution on YOUR website!
For lines to be parallel, they must have the same slope.
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\n" ); document.write( "You are given the equation:
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\n" ); document.write( "-5y=10x+32
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\n" ); document.write( "You can find the slope of the graph of this equation by \"rearranging\" the given equation
\n" ); document.write( "into the slope intercept form of y = mx + b. [In this form m (the multiplier of x] is the
\n" ); document.write( "slope and b is the value on the y-axis where the graph crosses (or intercepts).
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\n" ); document.write( "So we need to solve the given equation for y. If we do that, the resulting equation
\n" ); document.write( "will be in the slope intercept form. Since the given equation has -5y, we can find y
\n" ); document.write( "by dividing all terms on both sides by -5, the multiplier of y. Dividing by -5 results in:
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\n" ); document.write( "y = (10/-5)x + (32/-5)
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\n" ); document.write( "The division causes the coefficient [or multiplier] of x to become -2 and the resulting
\n" ); document.write( "equation is:
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\n" ); document.write( "y = -2x - (32/5)
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\n" ); document.write( "Since this is in slope intercept form, we now know that the graph of the given equation
\n" ); document.write( "crosses the y-axis at -32/5 and the graph has a slope of -2 (it goes vertically down 2
\n" ); document.write( "units every time it moves horizontally to the right 1 unit).
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\n" ); document.write( "Since the line we are looking for is now known to have a slope of -2 (it must have the
\n" ); document.write( "same slope as the given line to be parallel), we can now write part of the slope intercept
\n" ); document.write( "form of the equation of this new line. The new line will be of the form:
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\n" ); document.write( "y = -2x + b
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\n" ); document.write( "The problem tells you that this line must go through the point (-1,1) which means that
\n" ); document.write( "the equation must be true when x = -1 and y = +1.
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\n" ); document.write( "So we can substitute these values for x and y in the equation of the new line. Therefore,
\n" ); document.write( "substitute these values into:
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\n" ); document.write( "y = -2x + b
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\n" ); document.write( "and you get:
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\n" ); document.write( "1 = -2(-1) + b
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\n" ); document.write( "Multiply out the first term on the right side and you get:
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\n" ); document.write( "1 = 2 + b
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\n" ); document.write( "Solve for b by subtracting 2 from both sides of the equation to get:
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\n" ); document.write( "1 - 2 = 2 - 2 + b
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\n" ); document.write( "which simplifies to:
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\n" ); document.write( "-1 = + b
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\n" ); document.write( "We now know that b = -1 so our equation for the new line becomes:
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\n" ); document.write( "y = -2x + b
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\n" ); document.write( "and by substituting -1 for b it is:
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\n" ); document.write( "y = -2x - 1
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\n" ); document.write( "That's the answer. And if you graphed the original equation and this new equation,
\n" ); document.write( "the graph would look like this:
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\n" ); document.write( "\"graph%28300%2C300%2C-20%2C20%2C-20%2C20%2C+-2x+-32%2F5%2C+-2x-1%29\"
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\n" ); document.write( "in which the green line (which crosses the y-axis at -1) represents the parallel line that
\n" ); document.write( "we found, and the other line is the graph of the equation you were originally given.
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\n" ); document.write( "Hope this helps you to understand the process of making a parallel line. Remember
\n" ); document.write( "that the slopes of the two lines must be the same.
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