Step-by-step explanation:
Note that since [tex]\triangle ABC \cong \triangle DEF,[/tex] we can see from the figure that [tex]\angle B[/tex] and [tex]\angle E[/tex] have the same measure.
a) To solve for the length of [tex]\overline{AB},[/tex] we write
[tex]3x + 6 = 4x \Rightarrow x = 6[/tex]
b) Since the two triangles are congruent, we can say that [tex]\angle A = \angle D[/tex] so we can write
[tex]6y + 12 = 8y + 2[/tex]
Solving for y, we get
[tex]2y = 10 \:\Rightarrow \:y = 5[/tex]
