Answer:
x = 12
Explanation:
Creating an equation
Angles in a triangle add up to 180 degrees.
This means that 6x - 19 + 3x + 7 + 84 = 180
Solving for x
6x - 19 + 3x + 7 + 84 = 180
==> combine like terms
9x + 72 = 180
==> subtract 72 from both sides
9x = 108
==> divide both sides by 9
x = 12