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Tuesday, October 12, 2021

2021/083) show that for no positive integers a, b,c can all the 3 expresssion a^2+b+c, b^2+a + c , c^2 + a +b be perfect squares

 Proof:

The samllest square above a^2 is a^2+2a+1. so we must have for a^2+b+c to be a prefect square

a^2 + b+ c \ge (a+1)^2

Or b+c \ge 2a + 1\cdots(1)

Similarly c+a \ge 2b + 1\cdots(2)

And a + b  \ge 2c + 1\cdots(3)

Adding above 3 equations we must have 2(a+b+c) >= 2(a + b+ c) + 3 or 0 \ge  3 which is contradiction

So above is impossible  or No solution exists 

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