Respuesta :

Space

Answer:

x = 10

General Formulas and Concepts:

Pre-Algebra

  • Order of Operations: BPEMDAS
  • Equality Properties

Geometry

  • All angles in a triangle add up to 180°

Step-by-step explanation:

Step 1: Set up equation

(x + 1)° + (10x - 7)° + (8x - 4)° = 180°

Step 2: Solve for x

  1. Combine like terms:                         19x - 10 = 180
  2. Isolate x term:                                   19x = 190
  3. Isolate x:                                            x = 10