document.write( "Question 68019This question is from textbook Finite Mathmatics
\n" ); document.write( ": If the lines passing through the points (1,a) and (4,-2) is parallel to the line passing through the points (2,8) and (-7,a+4), what is the value of a? \n" ); document.write( "
Algebra.Com's Answer #48434 by ankor@dixie-net.com(22740)\"\" \"About 
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If the lines passing through the points (1,a) and (4,-2) is parallel to the line passing through the points (2,8) and (-7,a+4), what is the value of a?
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\n" ); document.write( "Find the slopes using the slope equation: m = \"%28%28y2-y1%29%29%2F%28%28x2-x1%29%29\"
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\n" ); document.write( "The first given points: x1 = 1, y1 = a, x2 = 4, y2 = -2, call the slope m1:
\n" ); document.write( "m1 = \"%28%28-2+-+a%29%29%2F%28%284+-+1%29%29\" = \"%28%28-2-a%29%29%2F3\"
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\n" ); document.write( "The 2nd given points: x1 = 2, y1 = 8, x2 = -7, y2 = (a+4); call the slope m2
\n" ); document.write( "m2 = \"%28%28%28a%2B4%29+-+8%29%29%2F%28%28-7+-+2%29%29\" = \"%28%28a+-4%29%29%2F-9\"
\n" ); document.write( "When lines are parallel, slopes are equal, m1 = m2 so we have:
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\n" ); document.write( "\"%28%28-2-a%29%29%2F3\" = \"%28%28a+-+4%29%29%2F-9\"
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\n" ); document.write( "Cross multiply and solve for a
\n" ); document.write( "-9(-2-a) = 3(a - 4)
\n" ); document.write( "18 + 9a = 3a - 12
\n" ); document.write( "9a - 3a = -12 - 18
\n" ); document.write( "6a = -30
\n" ); document.write( "a = -30/6
\n" ); document.write( "a = -5
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\n" ); document.write( "You can check the solution by finding the 2 slopes to see if they are equal. \n" ); document.write( "
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