A student places two charged objects near each other. the objects repel each other. the student concluded that the objects must both be negative. do you agree? explain.

No because, for an object to repel another object, the two must either be negative, or positive. It doesn't necessarily have to be negative, both of them could be positive as well. As long as both the charges are the same, the objects will repel from each other since like charges repel.