Respuesta :

These are consecutive angles meaning they have the same angle measure
so
4x + 21 = 65
subtract 21 from both sides
4x = 44
divide both sides by 4 to isolate x
x = 11

to check:
65 =?= 4x + 21
65 =?= 4(11) + 21
65 =?= 44 + 21
65 = 65

Hope this helps :)
Kaikerscupcake
If you are looking to x:

Since the two angles are vertical they are congruent.

65= 4x + 21

Subtract 21 from both sides.

44=4x

Divide by 4 into both sides.

11=x

I hope this helps!
~cupcake