Question 752246
Call the year 1990 {{{ 0 }}}
Then, 1994 = {{{ 4 }}}
and, 1998 = {{{ 8 }}}
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Now you have 2 points on a straight line:
( 4, 3550 )
( 8, 3270 )
Plug these points into the general point-slope formula
{{{ ( P - 3270 ) / ( t - 8 ) = ( 3550 - 3270 ) / (  4 - 8 ) }}}
{{{ ( P - 3270 ) / ( t - 8 ) = 280 / (  -4 ) }}}
{{{ ( P - 3270 ) / ( t - 8 ) = -70 }}}
{{{ P - 3270 = -70*( t-8 ) }}}
{{{ P - 3270 = -70t + 560 }}}
{{{ P = -70t + 3830 }}}
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In 2007, {{{ t = 17 }}}
{{{ P = -70*17 + 3830 }}}
{{{ P = -1190 + 3830 }}}
{{{ P = 2640 }}}
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check:
( 8,3270 )
{{{ P = -70t + 3830 }}}
{{{ 3270 = -70*8 + 3830 }}}
{{{ 3270 = -560 + 3830 }}}
{{{ 3270 = 3270 }}}
OK
You can check the other point