When you have a coefficient in front of the "x^2" value, you have to multiply it by the end value (4)
so you want a set of integers that will add up to 29, by multiple to (7 x 4) = 28
The only numbers like that are 28 and 1, they add up to 29 and multiply to 29
Therefore, rewrite it like this 7x^2 + 28x + x + 4
and then factor out the 7x in the first two terms, to get this
7x(x+4) + x + 4, then factor out 1 in the latter two terms to get this:
7x(x+4) +1(x+4), then use grouping to combine what you've got:
The factors are: {{ (7x+1)(x+4) }}
