The sum of the digits of two-digit number is 7. when the digits are subtracted, the number is -5. find the number

Question

I need help with this answer.

Answer 1

Let xy be the two digit number

 

x+y = 7

x-y = -5   add the two equations

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2x = 2

x = 1

 

y = 6

 

The number is 16

 

1+6 = 7

1-6 = -5