59.5k views
5 votes
Which of the following equations is an identity?

a) 2x + 5 = 3x - 1

b) 4(x - 2) = 2x + 3

c) 3(2x + 1) = 2(x + 3)

d) 5(x + 2) = 2x - 1

1 Answer

3 votes

Final answer:

None of the equations provided (2x + 5 = 3x - 1, 4(x - 2) = 2x + 3, 3(2x + 1) = 2(x + 3), 5(x + 2) = 2x - 1) are identities since each one results in a specific solution for x rather than being true for all x.

Step-by-step explanation:

The question concerns identifying which of the following equations is an identity:

  • 2x + 5 = 3x - 1
  • 4(x - 2) = 2x + 3
  • 3(2x + 1) = 2(x + 3)
  • 5(x + 2) = 2x - 1

An identity in algebra is an equation that is true for all values of the variable involved. To test for an identity, we simplify and solve each equation.

  1. For a), we get x = 6, which is not true for all x, so it's not an identity.
  2. For b), we get x = ⅔ or x = 3.5, which is also not true for all x.
  3. For c), simplifying both sides yields 6x + 3 = 2x + 6, which when solved for x gives x = ⅔. This is not an identity either.
  4. For d), the simplification gives 5x + 10 = 2x - 1. Solving this equation results in x = -⅓ or x = -3.7, thus it is not an identity.

None of the options provided are identities because all result in specific solutions and are not true for all values of x.

No related questions found