Question 614905
Plot population in millions on the vertical axis, call it {{{ p }}}
Plot the year on the horizontal axis, call it {{{ t }}}
Call 1990 {{{0}}}
The slope is:
{{{ ( 153 - 147 ) / ( 1998 - 1991 ) = 6/7 }}}
The equation so far is:
{{{ p = (6/7)*t + b }}}
Plug in the point ( 1, 147 )
{{{ 147 = (6/7)*1 + b }}}
{{{ 1029 = 6 + 7b }}}
{{{ 7b = 1023 }}}
{{{ b = 146.14 }}}
The equation is {{{ p = (6/7)*t + 146.14 }}}
In 2017,
{{{ p = ( 6/7 )*27 + 146.14 }}}
{{{ p = 23.143 + 146.143 }}}
{{{ p = 169.286 }}}
The population in 2017 will be 169,286,000
check:
The slope should be 6/7
{{{ ( 169.286 - 153 ) / ( 27 - 8 ) }}}
{{{ 16.286 / 19 = .8572 }}}
{{{ 6/7 = .8571 }}} 
close enough