Which equation shows the quadratic formula used correctly to solve 5x² + 3x + 4 = 0 for x?

To solve the quadratic equation 5x² + 3x + 4 = 0 using the quadratic formula, we start by recalling the formula itself. The quadratic formula is:

x = (-b ± √(b² – 4ac)) / (2a)

In our equation, we can identify the coefficients as follows:

  • a = 5
  • b = 3
  • c = 4

Now, we can substitute these values into the quadratic formula. First, we calculate the discriminant (the part under the square root):

b² – 4ac = 3² – 4(5)(4) = 9 – 80 = -71

Since the discriminant is negative, we know that the solutions for x will be complex numbers. Now, substituting the values into the quadratic formula gives us:

x = (−3 ± √(−71)) / (2 * 5)

This simplifies to:

x = (−3 ± i√71) / 10

Here, i represents the imaginary unit. Therefore, the equation showing the quadratic formula used correctly to solve 5x² + 3x + 4 = 0 for x is:

x = (−3 ± i√71) / 10

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