Answer: What is a factor?
A factor is a a divisor of an integer n, also called a factor of n, is an integer m that may be multiplied by some integer to produce n. In this case, one also says that n is a multiple of m. An integer n is divisible by another integer m if m is a divisor of n; this implies dividing n by m leaves no remainder.
Step-by-step explanation: Why can’t certain expressions be factored?
Because there are no common factors other than 1 the constants cannot be factored. And, because there is no x in the second term (10), we cannot factor an x out of the two terms.