The number B is 78 of the number A. if the number a is 56, then the number B is 78______ If B is 56, then a is 56______ ． | Math enthusiast | Mathematical art

The number B is 78 of the number A. if the number a is 56, then the number B is 78 If B is 56, then a is 56 ．

(1) 56 × 78 = 49; (2) 56 △ 78 = 64

The sum of the reciprocal of two natural numbers is one seventh. The two natural numbers are 〔 and 〕

1 / x + 1 / y = (x + y) / xy = 1 / 7, so y = 7x / (X-7) = 7 + 49 / (X-7)
Because X and y are natural numbers, then X-7 is a positive divisor of 49, so X-7 = 1,7,49
So x = 8,14,56 (x, y), so the solutions are (8,56), (14,14) and (56,8)

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