Respuesta :

Space

Answer:

3. r = -8

4. x = -5

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

Step-by-step explanation:

Step 1: Define equation

2(-5r + 2) = 84

Step 2: Solve for r

  1. Divide 2 on both sides:                    -5r + 2 = 42
  2. Subtract 2 on both sides:                 -5r = 40
  3. Divide -5 on both sides:                    r = -8

Step 3: Check

Plug in r into the original equation to verify it's a solution.

  1. Substitute in r:                   2(-5(-8) + 2) = 84
  2. Multiply:                             2(40 + 2) = 84
  3. Add:                                   2(42) = 84
  4. Multiply:                             84 = 84

Here we see that 84 does indeed equal 84.

∴ r = -8 is a solution of the equation.

Step 4: Define equation

264 = -8(-8 + 5x)

Step 5: Solve for x

  1. Divide both sides by -8:                    -33 = -8 + 5x
  2. Add 8 to both sides:                          -25 = 5x
  3. Divide 5 on both sides:                      -5 = x
  4. Rewrite:                                               x = -5

Step 6: Check

Plug in x into the original equation to verify it's a solution.

  1. Substitute in x:                    264 = -8(-8 + 5(-5))
  2. Multiply:                               264 = -8(-8 - 25)
  3. Subtract:                              264 = -8(-33)
  4. Multiply:                               264 = 264

Here we see that 264 does indeed equal 264.

∴ x = -5 is a solution of the equation.

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