Answer:
True
fo example: 3•3 = 9 (=2•4+1)
5•7 = 35 (=2•17+1)
11•13 = 143 (=2•71+1)
Explanation:
If k is any integer then 2k is even number and 2k+1 is odd number
If n is any other integer then 2n+1 is also some odd number
Their product:
(2k + 1)(2n + 1) = 2k•2n + 2•1k + 1•2n + 1•1 = 2(2kn + k + n) + 1
k,n are integers so 2kn also is integer.
Sum of integers is integer too, so if we name 2kn+k+n = z, then product of any two odd integers is 2z+1 which is an odd number.