Respuesta :

Answer:

x = 21

Step-by-step explanation:

The 2 angles form a straight angle and are supplementary, thus

7x + 9 + 2x - 18 = 180, that is

9x - 9 = 180 ( add 9 to both sides )

9x = 189 ( divide both sides by 9 )

x = 21

Answer:

x = 21

Step-by-step explanation:

The 2 angles form a straight angle and are supplementary

7x + 9 + 2x - 18 = 180

9x - 9 = 180

9x = 189

x = 21