what is the factor of : (y-z)^2 + (y-z) - 42 and 1+11x^2+36x^4?

"What are the factors of .... and of .. ?"
1.
Put u = y-z. Then the expression is a quadratic:
u^2 + u - 42; find two numbers a and b such that ab = -42 and a + b = 1
(or ab = 42 and a - b = 1).
This leads to (u+7)*(u-6), = (y-z+7) (y-z-6)
2.
36x^4 + 11x^2 + 1 contains only even powers of x; so put u = x^2.

(Should that be "13x^2" in the middle? If not, this gets very messy.)
36u^2 + 13u + 1 = (9u + 1) (4u + 1)
However, for 36u^2 + 11u + 1, there are no real factors; but that is not necessarily the case for the expression in x .
We look for (6x^2 + 1)^2 - a^2 x^2, and use the difference of two squares.
36u^2 + 11u + 1 = 36u^2 + 12u + 1 - u
= (6x^2 + 1)^2 - x^2
= (6x^2 - x + 1) (6x^2 + x 1); and neither bracket factorises further.

i) (y-z+7)(y-z-6)
ii) No factors