igcse math (quadratic functions)
given the equation: x^2 + 5x - 14
use the discriminant to decide if there are two real and different roots, two equal roots or no real roots

Respuesta :

Answer:

2 real different roots

Step-by-step explanation:

Discriminant determines the number of real solutions of a quadratic equation. The formula of discriminant goes by:

[tex]\displaystyle{D = b^2-4ac}[/tex]

The formula is derived from a quadratic formula which is:

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

The expression inside the square root is discriminant. The discriminant says that:

  • There are 2 real different roots if the discriminant (D) is greater than 0. (D > 0)
  • There is 2 real double roots (same roots) if the discriminant (D) is equal to 0. (D = 0)
  • There are no real roots (imaginary or complex roots) if the discriminant (D) is less than 0. (D < 0)

From the equation [tex]\displaystyle{x^2+5x-14}[/tex], determine the coefficients of equation:

  • a = 1
  • b = 5
  • c = -14

Therefore, substitute the coefficients’ values in the discriminant:

[tex]\displaystyle{D=5^2-4(1)(-14)}\\\\\displaystyle{D=25-4(-14)}\\\\\displaystyle{D=25+56}\\\\\displaystyle{D=81}[/tex]

Since the discriminant is greater than 0, we can conclude that this equation will have 2 real different roots.