Question 32268
Linear-equations/31502: When using the quadratic formula to solve a quadratic equation (ax2 + bx + c = 0), the discriminant is b2 - 4ac. This discriminant can be positive, zero, or negative.
Create three unique equations where the discriminant is positive, zero, or negative. For each case, explain what this value means to the graph of y = ax2 + bx + c.

1 solutions
Answer 18248 by venugopalramana(1268) About Me  on 2006-03-28 05:24:24 (Show Source):
When using the quadratic formula to solve a quadratic equation (ax2 + bx + c = 0), the discriminant is b2 - 4ac. This discriminant can be positive, zero, or negative.
Create three unique equations where the discriminant is positive
Y=X^2-5X+6=0
D=5^2-4*6=25-24=1
Y HAS POSITIVE AND NEGATIVE VALUES
, zero,
Y=X^2-4X+4=0
D=4^2-4*4=0
Y IS ALWAYS >=0
or negative
Y=X^2+4=0
D=0-4*4=-16
Y IS ALWAYS POSITIVE.(OR IT CAN BE ALWAYS NEGATIVE...AS IN CASE OF Y=-X^2)
. For each case, explain what this value means to the graph of y = ax2 + bx + c.
graph( 600, 600, -5, 5, -10, 10, x^2-5*x+6,x^2-4*x+4,x^2+4)