Respuesta :

Space

Answer:

15

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  

Equality Properties

  • Multiplication Property of Equality
  • Division Property of Equality
  • Addition Property of Equality
  • Subtraction Property of Equality

Step-by-step explanation:

Step 1: Define

Identify

5a - 10b = 45

b = 3

Step 2: Solve for a

  1. Substitute in b [Equation]:                                                                                5a - 10(3) = 45
  2. Multiply:                                                                                                             5a - 30 = 45
  3. [Addition Property of Equality] Add 30 on both sides:                                  5a = 75
  4. [Division Property of Equality] Divide 5 on both sides:                                  a = 15

Answer:

a=3

Step-by-step explanation:

5a-10b=45

when b=3

5a-10×3=45

5a-30=45

collect like terms

5a=45-30

5a=15

a=3