Math 7B. Pattering and Algebraic Reasoning. Spring25 Sample work

Question 3
Select ALL of the expressions that are equivalent to
4 (x+3) - 10 + 6x
10x - 7
-2x - 7
2 (5x + 1)
2 (8x + 1)
4x + 3 - 10 + 6x
4x + 12 - 10 + 6x

1 answer

To determine which expressions are equivalent to \( 4(x + 3) - 10 + 6x \), we first need to simplify this expression step by step.

  1. Distribute the \( 4 \) to \( (x + 3) \):

    \[ 4(x + 3) = 4x + 12 \]

  2. Substitute back into the expression:

    \[ 4x + 12 - 10 + 6x \]

  3. Combine like terms:

    \[ 4x + 6x + 12 - 10 = 10x + 2 \]

So, \( 4(x + 3) - 10 + 6x \) simplifies to \( 10x + 2 \).

Now let's compare this with the provided options:

  1. \( 10x - 7 \): Not equivalent (it differs by +9).
  2. \( -2x - 7 \): Not equivalent (wrong direction and different coefficients).
  3. \( 2(5x + 1) \): Let's simplify this: \[ 2(5x + 1) = 10x + 2 \quad \text{(Equivalent)} \]
  4. \( 2(8x + 1) \): Let's simplify this: \[ 2(8x + 1) = 16x + 2 \quad \text{(Not equivalent)} \]
  5. \( 4x + 3 - 10 + 6x \): Let's simplify: \[ 4x + 6x + 3 - 10 = 10x - 7 \quad \text{(Not equivalent)} \]
  6. \( 4x + 12 - 10 + 6x \): We have already simplified this earlier: \[ 4x + 6x + 12 - 10 = 10x + 2 \quad \text{(Equivalent)} \]

Thus, the expressions equivalent to \( 4(x + 3) - 10 + 6x \) are:

  • \( 2(5x + 1) \)
  • \( 4x + 12 - 10 + 6x \)

So, the final answer is:

  • \( 2(5x + 1) \)
  • \( 4x + 12 - 10 + 6x \)