Is the number 9 + -9 rational or irrational?

1 answer

The expression \( 9 + -9 \) simplifies to \( 0 \). A number is considered rational if it can be expressed as the quotient of two integers, where the denominator is not zero. Since \( 0 \) can be expressed as \( \frac{0}{1} \) (or any other non-zero denominator), it is a rational number. Therefore, the result of \( 9 + -9 \) is rational.