Factorise the following quadratic polynomial by splitting the middle term: $12x^2 + 23x + 5$.

(N/A) To factorise $12x^2 + 23x + 5$ by splitting the middle term,we need to find two numbers whose product is $12 \times 5 = 60$ and whose sum is $23$.
These two numbers are $20$ and $3$.
Now,rewrite the middle term $23x$ as $20x + 3x$:
$12x^2 + 20x + 3x + 5$
Group the terms:
$(12x^2 + 20x) + (3x + 5)$
Factor out the common terms from each group:
$4x(3x + 5) + 1(3x + 5)$
Finally,factor out the common binomial $(3x + 5)$:
$(4x + 1)(3x + 5)$