Question 489762
A graphing calculator won't make much difference.
Linear equations and matrices should work, espically Gaussian elimination.
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One issue you all may be having is the definition of H, Y, and L.  As stated above these are all fractions per acre, then when you are done, multiply all by 220.
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I would have started with the equation
H + Y + L = 220 which will result in the answer requested without further step and is easier to work with than those biggies.
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Of course, it's silly to try to use up all your resources,  This situation cries out for Linear Programming (needed: Prices per crop), but that is another subject.