∠A and \angle B∠B are vertical angles. If m\angle A=(3x-30)^{\circ}∠A=(3x−30) ∘
and m\angle B=(2x-9)^{\circ}∠B=(2x−9)
∘
, then find the value of x.

Step-by-step explanation:

So we know that:

And that the two angles are vertical angles.

Since they are vertical angles, their measurements are equivalent. Thus, to find x, set the equations equal to each other:

Now, solve for x. Add 30 to both sides. The left side cancels:

Now, subtract 2x from both sides. The right cancels:

Thus, the value of x is 21.