Respuesta :

Answer:

  x = 4

Step-by-step explanation:

An exterior angle of a triangle is equal to the sum of the remote interior angles.

  18x +5 = (46) +(-1 +8x)

  10x = 40 . . . . . . . . . . . . . subtract (5+8x) from both sides, simplify

  x = 4 . . . . . . divide by 10

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Additional comment

The exterior angle is (18)(4) +5 = 77°. The marked unknown interior angle is -1+(8)(4) = 31°. The sum of the two remote interior angles is 46°+31° = 77°. The unmarked interior angle is 180°-77° = 103°.