Question 1057332
I'll call 1960 {{{ x = 0 }}} on the horizontal axis
1990 = {{{ x = 30 }}} 
Plot pounds, {{{ y }}}, consumed on the vertical axis
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For pork consumption, you are given the 2 points
( 0, 62 )
( 30, 52 )
For chicken consumption, you are given the 2 points
( 0, 31 )
( 30, 66 )
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Use point-slope formula:
For pork:
{{{ ( y - 52 ) / ( x - 30 ) = ( 62 - 52 ) / ( 0 - 30 ) }}}
{{{ ( y - 52 ) / ( x - 30 ) = 10 / (-30) }}}
{{{ ( y - 52 ) / ( x - 30 ) = -1/3 }}}
{{{ y - 52  = ( -1/3 )*( x - 30 ) }}}
{{{ y - 52 =  (-1/3)*x + 10 }}}
{{{ y = (-1/3)*x + 62 }}}
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For chicken:
{{{ ( y - 31 ) / ( x - 0 ) = ( 66 - 31 ) / ( 30 - 0 ) }}}
{{{ ( y - 31 ) / ( x - 0 ) = 35 / 30 }}}
{{{ ( y - 31 ) / ( x - 0 ) = 7/6 }}}
{{{ y - 31 = (7/6)*x }}}
{{{ y = (7/6)*x + 31 }}}
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For what values of {{{ x }}} is {{{ y[c] > y[p] }}} ?
{{{ ( 7/6 )*x + 31 > ( -1/3 )*x + 62 }}}
{{{ ( 7/6 )*x + ( 2/6 )*x  > 31 }}}
{{{ (9/6)*x > 31 }}}
{{{ x > (2/3)*31 }}}
{{{ x > 20.667 }}}
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After 1920 and 9 months, chicken consumption
is greater
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Here are plots of the 2 lines:
{{{ graph( 400, 400, -4, 40, -8, 80, (7/6)*x + 31, (-1/3)*x + 62 ) }}}