Answer:
B. 1, 2, 5, 10
Step-by-step explanation:
The requirement is that every element in the domain must be connected to one - and one only - element in the codomain.
A classic visualization consists of two sets, filled with dots. Each dot in the domain must be the start of an arrow, pointing to a dot in the codomain.
So, the two things can't can't happen is that you don't have any arrow starting from a point in the domain, i.e. the function is not defined for that element, or that multiple arrows start from the same points.
But as long as an arrow start from each element in the domain, you have a function. It may happen that two different arrow point to the same element in the codomain - that's ok, the relation is still a function, but it's not injective; or it can happen that some points in the codomain aren't pointed by any arrow - you still have a function, except it's not surjective.
Yes and no. A negative number and it's opposite are 'integers.' Yes, a negative and a negative multiplied together give you a positive. The two negative signs cancel out making it positive. But no, a positive and a positive multiplied together do not give you a negative. When you subtract positive numbers you can get a negative, but not when multiplying. If you were to do a positive times a negative it would be negative because the positive can't cancel it out. Example: -3 · -3 = 9. [] 3 · 3 = 9. [] -3 · 3 = -9. Other than the positive number part, the statement is true about the negatives. I hope that helped!
