? asked in Science & MathematicsMathematics · 9 years ago

Identify the solutions to the equation 2x2 + 5x = 3 when you solve by factoring.?

Hey does anyone know how to solve this? I tried to solve it using the quadratic formula but i didn't get any of the answer choices. Help!!

Identify the solutions to the equation 2x2 + 5x = 3 when you solve by factoring.

1. 1/2, –3

2. –1/2, 3

3. 2/3, –3

4. –2/3, 3

3 Answers

Relevance
  • TomV
    Lv 7
    9 years ago
    Best Answer

    Well, the solution is the same whether you solve by factoring, completing the square, quadratic formula, or simply flat out guessing.

    2x² + 5x - 3 = 0

    (2x - 1)(x + 3) = 0

    x = 1/2, -3

    1. is the correct choice.

    By the quadratic formula:

    x = [-5 ± √(25 + 24)]/4 = -5/4 ± 7/4 = -12/4, 2/4 = 1/2, -3

    By completing the square:

    2x² + 5x - 3 = 0

    x² + (5/2)x + 25/16 - 25/16 - 3/2 = 0

    (x + 5/4)² = 49/16

    x = -5/4 ± 7/4 = 1/2, -3

    ...

  • 9 years ago

    2x² + 5x = 3

    2x² + 5x - 3 = 0

    (2x - 1)(x + 3) = 0

    x = 1/2, -3

    P.S. When you used the quadratic formula, was c = -3?

  • Pappy
    Lv 4
    9 years ago

    Use this notation when writing exponents ; x squared... is x^2

    2x^2 + 5x = 3 can be factored as follows:

    (2x - 1) (x + 3)

    --------->(2x - 1) = 0

    ---------------> 2x = +1

    -------------------------------> x = +1/2

    ------------> (x + 3) = 0

    -------------------------------> x = - 3

    The answer is choice #1.

Still have questions? Get your answers by asking now.