Respuesta :

Space

Answer:

x = 20

General Formulas and Concepts:

Order of Operations: BPEMDAS

All angles in a triangle add up to 180°.

Explanation:

Step 1: Set up equation

90 + 31 + 3x - 1 = 180

Step 2: Solve for x

  1. Combine like terms:                              120 + 3x = 180
  2. Subtract 120 on both sides:                  3x = 60
  3. Divide by 3 on both sides:                    x = 20