Of 7 non-zero factors, 3 are positive, so the other 4 are negative. Multiplying two negatives gives a positive number. So on its own, the product of all the negatives is positive, and multiplying by the other 3 positive numbers makes the overall product positive.
Step-by-step explanation: This is one of those sneaky questions where you think there is no definite answer, but don't despair. There is an answer. You have 7 numbers 3 of them are positive which means greater than 0. Let's pick them 345 = 60 That part's easy. Those 3 numbers give a plus result. Now try the other 4 numbers -3 -2 - 1-4 Do you see what's going to happen. You have -3* - 2 = 6 then you get - 1*-4 = 4 All of a sudden you get a positive result 6 * 4 = 24 60 * 24 = 1440 So the answer is any 3 plus numbers multiplied by 4 minus numbers gives a plus result.