This week in pre-calculus 11, we learned about the discriminant. The discriminant is the radicand in the quadratic formula, b2– 4ac.
The discriminant is used to indicate whether the quadratic formula has 2 real roots or unequal roots, 1 real root or 2 equal roots, or no real roots.
x > 0: 2 real roots / 2 unequal roots.
x = 0: 1 real root / 2 equal roots.
x < 0: 0 real roots.
We use the quadratic equation to figure out which numbers are a, b, and c.
ax2 + bx + c = 0
Ex:
4x2 + 3x + 8 = 0
a = 4, b = 3, c = 8
b2– 4ac
32– 4(4)(8)
9 – 128
= -119
Seeing as the answer is negative, there are no real roots because -119 is less than 0.