After simplifying, which expressions are equivalent? Check the three that apply.(3 points)

Responses

(−3.9b+a)+(−1.7b+4.9a)
open paren negative 3 point 9 b plus A close paren plus open paren negative 1 point 7 b plus 4 point 9 A close paren

(2.5a+1.6b)+(3.4a+4b)
open paren 2 point 5 A plus 1 point 6 b close paren plus open paren 3 point 4 A plus 4 b close paren

5.9a−5.6b
5 point 9 A minus 5 point 6 b

−0.4b+(6b−5.9a)
negative 0 point 4 b plus open paren 6 b minus 5 point 9 A close paren

(3.4a−1.7b)+(2.5a−3.9b)

1 answer

To determine which expressions are equivalent, let’s simplify each expression step by step.

  1. First Expression: \[ (-3.9b + a) + (-1.7b + 4.9a) \] Combining like terms: \[ = a + 4.9a + (-3.9b - 1.7b) = 5.9a - 5.6b \]

  2. Second Expression: \[ (2.5a + 1.6b) + (3.4a + 4b) \] Combining like terms: \[ = 2.5a + 3.4a + 1.6b + 4b = 5.9a + 5.6b \]

  3. Third Expression: \[ 5.9a - 5.6b \] This is simplified as it stands.

  4. Fourth Expression: \[ -0.4b + (6b - 5.9a) \] Combining like terms: \[ = -0.4b + 6b - 5.9a = 5.6b - 5.9a \] Note that this can be rearranged to: \[ = -5.9a + 5.6b \]

  5. Fifth Expression: \[ (3.4a - 1.7b) + (2.5a - 3.9b) \] Combining like terms: \[ = 3.4a + 2.5a - 1.7b - 3.9b = 5.9a - 5.6b \]

Now let’s summarize the results:

  • First Expression simplifies to \( 5.9a - 5.6b \)
  • Second Expression simplifies to \( 5.9a + 5.6b \)
  • Third Expression is \( 5.9a - 5.6b \)
  • Fourth Expression simplifies to \( -5.9a + 5.6b \)
  • Fifth Expression simplifies to \( 5.9a - 5.6b \)

From the above, the equivalent expressions are:

  • First Expression: \( 5.9a - 5.6b \)
  • Third Expression: \( 5.9a - 5.6b \)
  • Fifth Expression: \( 5.9a - 5.6b \)

Therefore, the three expressions that are equivalent are:

  1. \( (-3.9b + a) + (-1.7b + 4.9a) \)
  2. \( 5.9a - 5.6b \)
  3. \( (3.4a - 1.7b) + (2.5a - 3.9b) \)

Please note that the second expression \( 5.9a + 5.6b \) and the fourth expression \( -5.9a + 5.6b \) are not equivalent to the others.