Question

The factors of $x^2+9x+18$ are:

Answer 1

If we compare the equation $x^2+9x+18$ with $a{x}^2+bx+c$

Now we can take numbers whose product is $ac$, i.e. 18 × 1

18 = 18 × 1 or 9 × 2 or 6 × 3And the sum of the numbers be $b$, so, from the above combinations only 6 + 3 = 9
$\therefore x^2+9x+18=x^2+6x+3x+6\times 3=x(x+6)+3(x+6)=(x+6)(x+3)$
Therefore, the factors of $x^2+9x+18$ are $(x+3)$ and $(x+6)$.

Hence, option b is the correct answer.