1. Algebra 2
5.6 Quadratic Formula
When factoring or completing the square won’t work, use Quadratic Formula!!
If ax2
+ bx + c = 0,
then x =
The _______________________ is the stuff under the radical. It tells you what kind/how
many solutions the quadratic has.
If the discriminant is positive there are ___________________ solutions.
If the discriminant is zero there is ____________________ solution.
If the discriminant is negative
there are ___________________________
solutions.
A solution is also called a _______________.
A root is how many times the graph (parabola) touches the _______________.
EX 1: What kind/how many solutions do the following have?
a) x2
– 6x + 10 = 0 b) x2
– 6x + 9 = 0 c) x2
– 6x + 8 = 0

2. Using the quadratic formula to solve an equation:
EX 2: Solve 2x2
+ x = 5
EX 3: Solve x2
– x = 5x – 9
EX 4: Solve – x2
+ 2x = 2
HW (due next week): p. 295 (24 – 40, 56 – 64 even)