Respuesta :

Space

Answer:

y = 54

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

  1. Brackets
  2. Parenthesis
  3. Exponents
  4. Multiplication
  5. Division
  6. Addition
  7. Subtraction
  • Left to Right

Algebra I

  • Equality Properties

Geometry

  • Congruency
  • All angles in a triangle add up to 180°

Step-by-step explanation:

Step 1: Define

3(x + 7)° = 63°

3(x + 7)° + 63° + y° = 180°

Step 2: Solve for x

  1. Divide 3 on both sides:                    x + 7 = 21
  2. Subtract 7 on both sides:                 x = 14

Step 3: Solve for y

  1. Substitute in x:                    3(14 + 7) + 63 + y = 180
  2. (Parenthesis) Add:              3(21) + 63 + y = 180
  3. Multiply:                               63 + 63 + y = 180
  4. Combine like terms:           y + 126 = 180
  5. Isolate y:                              y = 54