The first answer choices are
D
F
G
J
The second answer choice was
H
L
K
E
The third answer choice was
G
F
H
K

J

L

K

Step-by-step explanation:

JKL is the only candidate to be congruent to ABC, because it shares at least one angle.

Since the sum of the angles in a triangle is always 180° (on a flat surface), we can calculate the missing values. wich indeed match with the given other values of each mentioned triangle

Note the JKL is not exactly congruent, because it's mirrored and flipped. but it's good enough for the reasoning.

x is variable or an unknown value to find

example:

2x = 5 which means x = 3

the value of v.w= -12.

step-by-step explanation:

we are given three vector r,v and w as:

r = < 5, -5, -2> ; v = < 2, -8, -8> ; w = < -2, 6, -5>

we know that r,v and w could also be represented as:

r=5i-5j-2k

v=2i-8j-8k

and w= -2i+6j-5k

where i,j and k are the unit vectors of x,y and z-axis respectively.

also we know that it has the following property:

i.i=1 ; j.j=1; k.k=1

and i.=j.i=i.k=k.i=j.k=k.j=0

i.e. when we multiply two vectors or we find it's dot product we need to only multiply the components of x coordinates with each other; y with each other and z with each other.

hence, v.w= (2i-8j- -2i+6j-5k)

                  = 2×(-2)+(-8)×(6)+(-8)×(-5)

                  = -4-48+40

                  = -12

hence, v.w= -12