Question

What is positive four plus negative four over negative nine plus negative seven

Answer 1

$\frac{4 + (-4)}{(-9) + (-7)} = \frac{4-4}{-9 -7} = \frac{0}{-16} = 0$

When 0 is in the numerator, then the whole fraction becomes equal to 0.

However if 0 is in the denominator, then it is undefined.