Which is not a property of the sides of a rectangle?

Multiplying an even number of negative numbers gives an answer that is choose from:

Find the vertex of the function given below y=x^2-6x+1

Offering 30 if a plus b plus c equals 68 and ab plus bc plus ca equals 1121, where a, b, and c are all prime numbers, find the value of abc. the answer is 1978 but i need an explanation on how to get that.