Question 969250
{{{  y = (1/4)*x - 2 }}} 
(8, -1 )
Any line parallel to the given line must
have slope = {{{ 1/4 }}}
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Use general point-slope formula
{{{ ( y -( -1 ) ) / ( x - 8 ) = 1/4 }}}
{{{ ( y + 1 ) / ( x - 8 ) = 1/4 }}}
Multiply both sides by {{{ 4*( x - 8 ) }}}
{{{ 4*( y + 1 ) = x - 8 }}}
{{{ 4y + 4 = x - 8 }}}
{{{ 4y = x - 12 }}}
{{{ y = ( 1/4 )*x - 3 }}}
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check:
does it go through ( 8, -1 ) ?
{{{  -1 = ( 1/4 )*8 - 3 }}}
{{{ -1 = 2 - 3 }}}
{{{ -1 = -1 }}}
OK
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{{{ y = -4x - 5 }}}
( 0,-1 )
Any line perpendicular to the given
line will have slope = 
{{{ m = -1 / ( -4 ) }}}
{{{ m = 1/4 }}}
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Use general point-slope formula
{{{ ( y -( -1 ) ) / ( x - 0 ) = 1/4 }}}
{{{ ( y + 1 ) / x = 1/4 }}}
Multiply both sidesby {{{ 4x }}}
{{{ 4*( y + 1 ) = x }}}
{{{ 4y + 4 = x }}}
{{{ 4y = x - 4 }}}
{{{ y = ( 1/4 )*x - 1 }}}
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check:
does it go through ( 0, -1 ) ?
{{{ -1 = ( 1/4 )*0 - 1 }}}
{{{ -1 = -1 }}}
OK