Respuesta :

mathstudent55

Answer:

x = 9

Step-by-step explanation:

Vertical angles are congruent, so their measures are equal.

4x + 6 = 7x - 21

Subtract 7x from both sides.

-3x + 6 = -21

Subtract 6 from both sides.

-3x = -27

Divide both sides by -3.

x = 9

Charles00

Because of the postulate "Vertical angles are equal" we can write the equation:

4x + 6 = 7x - 21

Then solve:

(4x + 6) + 21 = (7x - 21) + 21

(4x + 27) - 4x = (7x) - 4x

27/3 = 3x/3

x = 9