Find all numbers for which the rational expression is undefined -12/5y.

The rational expression is defined for every real number is this correct?

correct if you meant (-12/5)y

incorrect if you meant -12/(5y)

for the last one, it would be all real numbers except y = 0

Yes, that is correct. The rational expression -12/5y is defined for every real number except for the values of y that would make the denominator, 5y, equal to zero.

To find the values for which the expression is undefined, we need to solve the equation 5y = 0.

Dividing both sides of the equation by 5, we get y = 0/5, which simplifies to y = 0.

Therefore, the rational expression -12/5y is undefined for y = 0. For all other real numbers, the expression is defined.