Question

Solve:

$x^2+9x+18$.

Answer 1

In the given polynomial $x^2+9x+18$,

The first term is $x^2$ and its coefficient is $1$.

The middle term is $9x$ and its coefficient is $9$.

The last term is a constant term $18$.

Multiply the coefficient of the first term by the constant $1\times 18=18$.

We now find the factor of $18$ whose sum equals the coefficient of the middle term, which is $9$ and then factorize the polynomial $x^2+9x+18$ as shown below:

$x^2+9x+18=x^2+3x+6x+18=x(x+3)+6(x+3)=(x+3)(x+6)$

Hence, $x^2+9x+18=(x+3)(x+6)$.