Answer:
A, C, D
Explanation:
Consider triangles NKL and NML. These triangles are right triangles, because

In these right triangles:
- reflexive property;
- given
Thus, triangles NKL and NML by HA postulate. Congruent triangles have congruent corresponding parts, so
![\overline{KN}\cong \overline{NM}\\ \\\overline{KL}\cong \overline{LM}\ [\text{option D is true}]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/cobinvp6yfz0ot4gkubykigk4iws8ea7wl.png)
Since

then
![7x-4=5x+12\\ \\7x-5x=12+4\\ \\2x=16\\ \\x=8\ [\text{option A is true}]\\ \\MN=KN=7\cdot 8-4=56-4=52\ [\text{option C is true}]](https://img.qammunity.org/2021/formulas/mathematics/middle-school/8lpg5om4cnyx88yr35mm708krdi36zw4fl.png)
Option B is false, because KN=52 units.
Option E is false, because LN is congruent KN, not LM