Question

Show that \(11 \times 19 \times 23 + 3 \times 11\) is not a prime number.

Answer 1

Factor out the common term \(11\) from the expression:

\[ 11 \times 19 \times 23 + 3 \times 11 = 11(19 \times 23 + 3) \]

Now simplify the expression inside the parentheses:

\[ 19 \times 23 = 437 \]

\[ 437 + 3 = 440 \]

Thus, the expression becomes:

\[ 11 \times 440 = 4840 \]

Since \(4840\) is divisible by \(11\), it is not a prime number.