What kind of solutions does 2x^2 + x - 1 = 0 have?

1 Answer
Serena D.
Apr 8, 2018

2 real solutions

Explanation:

You can use the discriminant to find how many and what kind of solutions this quadratic equation has.

Quadratic equation form: ax^2+bx+c, in this case a is 2, b is 1 and c is -1

Discriminant: b^2-4ac

Plug 2, 1, and -1 in for a, b, and c (and evaluate):

1^2-4*2*-1

1-4*2*-1

1-(-8)

9 rarr A positive discriminant indicates that there are 2 real solutions (the solutions can be positive, negative, irrational, or rational, so long as they are real)

Negative discriminants indicate that the quadratic function has 2 imaginary (involving i, the square root of -1) solutions.

Discriminants of 0 indicate that the quadratic function has 1 real solution. The quadratic function can be factored into the perfect square of something (such as (x+6)^2, which has a discriminant of 0)

Related questions
See all questions in Solutions Using the Discriminant
Impact of this question
4344 views around the world
You can reuse this answer
Creative Commons License