Question 935900
{{{ y = 275 - 8x }}}
The x-intercept is the point ( x,0 )
Since {{{ y = 0 }}} at the x-intertcept, this
is the point where the remaining gallons
of oil in the tank = {{{ 0 }}}, and the value 
of {{{ x }}} will be the number of days to
use up all {{{ 275 }}} gallons
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The tank will be half full when the remaining
gallons = {{{ 275/2 }}}, so I can say:
{{{ 275/2 = 275 - 8x }}}
Multiply both sides by {{{ 2 }}}
{{{ 275 = 550 - 16x }}}
{{{ 16x = 550 - 275 }}}
{{{ 16x = 275 }}}
{{{ x = 17.1875 }}}
The tank will be half full during the 17th day