College

Find the discriminant of the quadratic equation [tex]-8x^2 - 13x = 0[/tex]. Then state the number and type of solutions for the equation.

Select the correct response:

A. 169; one rational solution
B. -116; two imaginary solutions
C. 169; two rational solutions
D. 169; two irrational solutions

Answer :

We start with the quadratic equation

[tex]$$-8x^2 - 13x = 0.$$[/tex]

Step 1: Identify the coefficients.
The standard form of a quadratic equation is

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

Here, we have
[tex]$$a = -8,\quad b = -13, \quad c = 0.$$[/tex]

Step 2: Compute the discriminant.
The discriminant of a quadratic equation is given by

[tex]$$D = b^2 - 4ac.$$[/tex]

Substitute the coefficients:

[tex]$$
D = (-13)^2 - 4(-8)(0) = 169 - 0 = 169.
$$[/tex]

Step 3: Determine the number and type of solutions.
Since the discriminant is positive ([tex]$D = 169 > 0$[/tex]), the quadratic equation has two distinct real solutions. Given that the equation factors easily as

[tex]$$x(-8x - 13) = 0,$$[/tex]

the solutions are

[tex]$$x = 0 \quad \text{and} \quad x = -\frac{13}{8}.$$[/tex]

Both solutions are rational.

Final Answer:
The discriminant is [tex]$169$[/tex]; therefore, the quadratic has two rational solutions.