Question 1006466
Usually they want the most profitable way to spend 
money on 2 or more crops
This question just wants to know how to split the 
available acres so that you end up spending the
exact amount of money you have available
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Let {{{ a }}} = acres of corn to be planted
{{{ 450 - a }}} = acres of wheat to be planted
{{{ 42a }}} = cost to plant {{{ a }}} acres of corn
{{{ 35*( 450 - a ) }}} = cost to plant {{{ 450 - a }}}
acres of wheat
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{{{ 42a + 35*( 450 - a ) = 16520 }}}
{{{ 42a + 15750 - 35a = 16520 }}}
{{{ 7a = 770 }}}
{{{ a = 110 }}}
and
{{{ 450 - a = 450 - 110 }}}
{{{ 450 - a = 340 }}}
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110 acres of corn and 340 acres of wheat
should be planted
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check:
{{{ 42a + 35*( 450 - a ) = 16520 }}}
{{{ 42*110 + 35*340 = 16520 }}}
{{{ 4620 + 11900 = 16520 }}}
{{{ 16520 = 16520 }}}
OK