Answer:
Hi there!
Question 1: Since they already did the first step for you, the reason why (-6)(-3) is a positive number is because a negative multiply by a negative equals a positive. Plus the (-6)(-3) comes out to be 18.
Question 2: The reason why his answer is incorrect is because he said (-3)(-5) = (-15) which is completely wrong, remember a negative multiplied by another negative must equal a positive. So the next step should be (15)(-2) which then equals to the correct answer: -30.