Answer:
[tex] x = 7[/tex]
Step-by-step explanation:
Value of the exterior angle is equal to the addition of the opposite interior angles in a triangle
[tex]19 + 20 = 6x - 3 \\ 39 = 6x - 3 \\ 39 + 3 = 6x \\4 2 = 6x \\ \frac{42}{6} = \frac{6x}{6} \\ x = 7[/tex]
