4) – 2x2 + 6x + 5 = 0
a. nonreal
b. real, irrational, and unequal
c. real, rational, and equal
d. real, rational, and unequal

Respuesta :

Answer:

b. real, irrational, and unequal

Step-by-step explanation:

Roots of a quadratic equation

The standard representation of a quadratic equation is:

[tex]ax^2+bx+c=0[/tex]

where a,b, and c are constants.

Solving with the quadratic formula:

[tex]\displaystyle x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}[/tex]

The argument of the radical is called the discriminant:

[tex]d=b^2-4ac[/tex]

The nature of the solutions of the equation depends on the value of d as follows:

  • If d is zero, there is only one real (and rational) root.
  • If d is positive, there are two real unequal roots. If also d is a perfect square, then the roots are also rational. If d is not a perfect square, the roots are irrational.
  • If d is negative, there are two unequal complex roots.

We are given the equation:

[tex]-2x^2+6x+5=0[/tex]

Here: a=-2, b=6, c=5. The discriminant is:

[tex]d=6^2-4(-2)(5)=36+80=116[/tex]

d = 116

Since d is positive and a non-perfect square, the roots are:

b. real, irrational, and unequal

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