document.write( "Question 83787: HI my homework says to \" write the equation of the line in slope-intercept form:
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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. \n" );
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Algebra.Com's Answer #60275 by bucky(2189)![]() ![]() ![]() You can put this solution on YOUR website! For lines to be parallel, they must have the same slope. \n" ); document.write( ". \n" ); document.write( "You are given the equation: \n" ); document.write( ". \n" ); document.write( "-5y=10x+32 \n" ); document.write( ". \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). \n" ); document.write( ". \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: \n" ); document.write( ". \n" ); document.write( "y = (10/-5)x + (32/-5) \n" ); document.write( ". \n" ); document.write( "The division causes the coefficient [or multiplier] of x to become -2 and the resulting \n" ); document.write( "equation is: \n" ); document.write( ". \n" ); document.write( "y = -2x - (32/5) \n" ); document.write( ". \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). \n" ); document.write( ". \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: \n" ); document.write( ". \n" ); document.write( "y = -2x + b \n" ); document.write( ". \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. \n" ); document.write( ". \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: \n" ); document.write( ". \n" ); document.write( "y = -2x + b \n" ); document.write( ". \n" ); document.write( "and you get: \n" ); document.write( ". \n" ); document.write( "1 = -2(-1) + b \n" ); document.write( ". \n" ); document.write( "Multiply out the first term on the right side and you get: \n" ); document.write( ". \n" ); document.write( "1 = 2 + b \n" ); document.write( ". \n" ); document.write( "Solve for b by subtracting 2 from both sides of the equation to get: \n" ); document.write( ". \n" ); document.write( "1 - 2 = 2 - 2 + b \n" ); document.write( ". \n" ); document.write( "which simplifies to: \n" ); document.write( ". \n" ); document.write( "-1 = + b \n" ); document.write( ". \n" ); document.write( "We now know that b = -1 so our equation for the new line becomes: \n" ); document.write( ". \n" ); document.write( "y = -2x + b \n" ); document.write( ". \n" ); document.write( "and by substituting -1 for b it is: \n" ); document.write( ". \n" ); document.write( "y = -2x - 1 \n" ); document.write( ". \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: \n" ); document.write( ". \n" ); document.write( " \n" ); document.write( ". \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. \n" ); document.write( ". \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. \n" ); document.write( ". \n" ); document.write( " |