#### Coefficient

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I'm stuck on this question: solve for x (x is an integer) 7x = -19 mod(9) .

Thank you for your help.

- Thread starter Coefficient
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I'm stuck on this question: solve for x (x is an integer) 7x = -19 mod(9) .

Thank you for your help.

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Then you can just try numbers 1 through 8 to see if any yield a product congruent to the number you found.

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7x ≡ -19[9]

7x ≡ -10[9]

7x ≡ -1[9]

7x ≡ 8[9]

But i couldn't understand how this would help me because the next question is to deduce the solutions of the equation : 7x-9y= -19

Thanks.

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Note that 9y = 0 (mod 9). So the solutions for 7x - 9y = -19 (mod 9) will be the solutions for 7x = -19 (mod 9) and y = anything.

7x ≡ -19[9]

7x ≡ -10[9]

7x ≡ -1[9]

7x ≡ 8[9]

But i couldn't understand how this would help me because the next question is to deduce the solutions of the equation : 7x-9y= -19

Thanks.

-Dan

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Thank youNote that 9y = 0 (mod 9). So the solutions for 7x - 9y = -19 (mod 9) will be the solutions for 7x = -19 (mod 9) and y = anything.

-Dan