How do I factor this... 5x2 9x-18?

Answer 1

Factoring means using primes to get the answer (I think). So 5 is a prime; 2 is prime-like (sometimes it's a prime, sometimes it's not -- I think it's a prime); nine turns into two primes 3 and 3; and negative eighteen turns into -1, 2, 3, 3. (The digits are your answer).