Question 67329
Make a little chart:
calorie intake......wt.gained
14000.................0
14000+3500............1
14000+2(3500).........2

If intake is 21000 the 1st 14000 gives no gain
But (21000-14000)/3500=7000/3500=2 lbs gained

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EQUATION:
Wt gain (calorie input)= (x-14000)/3500
or
wt gain(x)= (x-14000)/3500
or 
gain(x)=(1/3500)x-4 where x is the calorie input
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{{{graph(600,400,0,21000,-1,2,(1/3500)x-4)}}}
Hope this helps.
Cheers,
Stan H.