#Finding number of pairs that satisfy the equation

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late scaffold
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the way i like to think about it is to pick the values 'one at a time'

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for the first one, what values can x be? then y is automatically determined right

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certainly x < n as we need y to be a positive integer. also if n is odd, can x be even?

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then just count all the possible x

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for the second question, part a already tells you the number of pairs (x+y, z). given x+y therefore, what are the possible values of (x, y)?

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if you count the possible x, that is exactly the number of pairs

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because for each x, there can only be one corresponding y that works

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you are right that x is an odd number, but the maximum value of x is not 3, its n-2

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i.e. count all the odd numbers between 1 and n-2

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cool

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first part fine then?

late scaffold
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basically yes

late scaffold
late scaffold
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yes, but then for each value of x+y, you can have different (x, y) with the same sum