document.write( "Question 756182: Given an equation of a line, find equations for lines parallel or perpendicular to it going through specified points. Find the appropriate equations and points from the table below. Simplify your equations into slope-intercept form.\r
\n" ); document.write( "\n" ); document.write( "For: Y= ¼ x -2; (8, -1)
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Algebra.Com's Answer #460125 by Cromlix(4381)\"\" \"About 
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Given line: y = 1/4x - 2
\n" ); document.write( "A line parallel to this line will
\n" ); document.write( "have an equal gradient = 1/4
\n" ); document.write( "Using the formula: and coords (8, -1)
\n" ); document.write( " y - b = m(x - a)
\n" ); document.write( " y + 1 = 1/4(x - 8)
\n" ); document.write( " 4y + 4 = x - 8
\n" ); document.write( " 4y = x - 8 - 4
\n" ); document.write( " 4y = x - 12
\n" ); document.write( " or
\n" ); document.write( " y = 1/4x -3 (Divided by 4)\r
\n" ); document.write( "\n" ); document.write( "A line perpendicular to y = 1/4x - 2
\n" ); document.write( "will have a gradient = -4
\n" ); document.write( "This is because when lines are perpendicular
\n" ); document.write( "to each other their gradients multiply together
\n" ); document.write( "to equal -1
\n" ); document.write( "This case: m1 * m2 = 1/4 * -4 = -1
\n" ); document.write( "Using the formula: and coords (8, -1)
\n" ); document.write( " y - b = m(x - a)
\n" ); document.write( " y + 1 = -4(x - 8)
\n" ); document.write( " y + 1 = -4x + 32
\n" ); document.write( " y = -4x + 32 - 1
\n" ); document.write( " y = -4x + 31\r
\n" ); document.write( "\n" ); document.write( "Hope this helps.
\n" ); document.write( ":-)
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