How many real number solutions? -7x^2+6x+3=0

2 Answers
May 28, 2018

discriminant = 120

two real irrational solutions.

Explanation:

-7x^2+6x+3

To solve this use the discriminant:

ax^2+bx+c

discriminant =b^2-4ac

=6^2-4*-7*3

=36-(-84)

=120

discriminant > 0: two real solutions.

discriminant = 0: one real solutions, bounce or double solution.

discriminant < 0: two imaginary solutions.

discriminant = perfect square: solution is rational

May 28, 2018

d = 120, therefore, there are two distinct real roots.

Explanation:

One can find the number of real solutions of a quadratic of the form, y = ax^2+bx+c, by computing the determinant, d = b^2-4ac

If d < 0, then there are no real roots.
If d=0, then there is one real root (called a repeated root).
If d >0, then there are two distinct real roots:

Given: -7x^2+6x+3=0

d = 6^2-4(-7)(3)

d = 120, therefore, there are two distinct real roots.