For the equation
$$\huge (x^2-7x+11)^{(x^2-13x+42)}=1$$
Let's consider the following cases.
Case 1:
$$ \large 1^y = 1 \quad \implies \quad x=2,5$$
Case 2:
$$ \large \underbrace{y^0}_{y \neq 0} = 1 \quad \implies \quad x=6,7$$
Case 3:
$$ \large \underbrace{(-1)^{2n}}_{n \in \mathbb{Z}} = 1 \quad \implies \quad x=3,4$$
For the last case, we need to check the that the (exponent) power is even when $x=3$,
$$3^2-13 \times (3)+42=12$$
and when $x=4$,
$$4^2-13 \times (4)+42=6$$
which works!
Final answer:
$$ x=2,3,4,5,6,7$$
Checking with Mathematica:
Solve[(x^2 - 7*x + 11)^(x^2 - 13 x + 42) == 1, x, Reals]
>> {{x -> 2}, {x -> 3}, {x -> 4}, {x -> 5}, {x -> 6}, {x -> 7}}