Question 740210
You are given the points ( 55, 2125 ) and ( 30, 585 )
Hours are plotted on the x-axis and Earnings are 
plotted on the y-axis.
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Use the general point-slope formula
{{{ ( E - 585 ) / ( h - 30 ) = ( 2125 - 585 ) / ( 55 - 30 ) }}}
{{{ ( E - 585 ) / ( h - 30 ) =  1540  /  25 }}}
{{{ ( E - 585 ) / ( h - 30 ) =  308  /  5 }}}
Multiply both sides by {{{ 5*( h - 30 ) }}}
{{{ 5*( E - 585 ) = 308*( h - 30 ) }}}
{{{ 5E - 2925 = 308h - 9240 }}}
{{{ 5E = 308h - 6315 }}}
{{{ E = 61.6h - 1263 }}} answer
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Check:
Does it go through ( 30,585 ) ?
{{{ E = 61.6h - 1263 }}}
{{{ 585 = 61.6*30 - 1263 }}} 
{{{ 585 = 1848 - 1263 }}}
{{{ 585 = 585 }}}
OK
Does it go through ( 55, 2125 ) ?
{{{ E = 61.6h - 1263 }}}
{{{ 2125 = 61.6*55 - 1263 }}}
{{{ 2125 = 3388 - 1263 }}}
{{{ 2125 = 2125 }}}
OK