Question 420396
You are given 2 data points that you can plot on a straight line
You can plot {{{T}}} = tax returns examined on the vertical axis,
and {{{x}}} = year on the horizontal axis.
given:
 Let x= 0 correspond to 1996
Then x = 10 corresponds to 2006
(0,1.9) and (10,1.2) are the points
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Use the point-slope formula:
{{{ ( T - 1.2) / (x - 10) = ( 1.9 - 1.2 ) / ( 0 - 10) }}}
{{{ ( T - 1.2 ) / ( x - 10 ) = .7/(-10) }}}
{{{ -10*( T - 1.2 ) = .7*( x - 10 ) }}}
{{{ -10T + 12 = .7x - 7 }}}
{{{ -10T = .7x - 19 }}}
{{{ T = -.07x + 1.9 }}}
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I'll check the formula for (10,1.2)
{{{ 1.2 = -.07*10 + 1.9 }}}
{{{ 1.2 = -.7 + 1.9 }}}
{{{ 1.2 = 1.2 }}}
OK
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Use the formula for 2008, which is  {{{x = 12}}}
{{{ T = -.07*12 + 1.9 }}}
{{{ T = - .84 + 1.9 }}}
{{{ T = 1.06 }}}
1.06 million returns examined in 2008
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Here's a plot:
{{{ graph( 400, 400, -2, 15, -1, 3, -.07x + 1.9) }}}