(ii) What will be the sign of the product if we multiply together:
(a) 8 negative integers and 3 positive integers?
(b) 5 negative integers and 4 positive integers?
(c) (–1), twelve times?
(d) (–1), 2m times, m is a natural number?
We know,
If the number of negative integers in a product is even, then the product is a positive integer and if the number of negative integers in a product is odd, then the product is a negative integer
And, any number of positive integers will always give a positive integer.
So, the sign of the product will be decided by the number of negative integers.
(a) 8 negative integers and 3 positive integers: Even number of negative integers, hence product is positive.
(b) 5 negative integers and 4 positive integers: Odd number of negative integers, hence product is negative.
(c) (–1), twelve times: Even number of negative integers, hence product is positive.
(d) (–1), 2m times, m is a natural number: Even number of negative integers, hence product is positive.