need help with these questions

Step-by-step explanation:
these are both quadratic curves, parabolas, and factorization means to express the 2 terms as multiplication with each other, so that the result would be the simplified function. in other words : find the two factor terms that make the whole function.
the advantage of factorization is to see the 2 solutions for y=0 right away.
the general form is
y = (x + a)(x + b)
and the y=0 solutions are then simply x = -a and x = -b.
in example 3 we have 2 different y=0 solutions, seemingly at x = 1 and x = 5.
that makes the factorization :
y = (x - 1)(x - 5)
when x becomes one of these values, the corresponding factor becomes 0 and therefore y becomes 0 too.
in example 4 we have only one y=0 solution (or so it seems; in fact there are still formally 2 solutions, they are just equal).
it is seemingly at x = -2.
since both solutions are equal, we have also two equal factors.
that makes the factorization
y = (x + 2)(x + 2) = (x + 2)²