How do you find the discriminant #x^2+2x-1#?

1 Answer
Mar 20, 2018

Answer:

See a solution process below:

Explanation:

The quadratic formula states:

For #ax^2 + bx + c = 0#, the values of #x# which are the solutions to the equation are given by:

#x = (-b +- sqrt(b^2 - 4ac))/(2a)#

The discriminate is the portion of the quadratic equation within the radical: #color(blue)(b)^2 - 4color(red)(a)color(green)(c)#

If the discriminate is:
- Positive, you will get two real solutions
- Zero you get just ONE solution
- Negative you get complex solutions

To find the discriminant for this problem substitute:

#color(red)(1)# for #color(red)(a)#

#color(blue)(2)# for #color(blue)(b)#

#color(green)(-1)# for #color(green)(c)#

#color(blue)(2)^2 - (4 * color(red)(1) * color(green)(-1)) =>#

#4 - (-4) =>#

#4 + 4 =>#

#8#

Therefore, this quadratic would have two real solutions.