SOLUTION: Find the value of "a" such that the equation ax^2 + 2x + 4 = 0 has exactly one solution. I'm not sure how to go about solving this problem. Any help is much appreciated.

Click here to see ALL problems on Quadratic Equations

Question 1118185: Find the value of "a" such that the equation ax^2 + 2x + 4 = 0 has exactly one solution.
I'm not sure how to go about solving this problem. Any help is much appreciated.

Found 2 solutions by ikleyn, Alan3354:
Answer by ikleyn(52780)   (Show Source):
You can put this solution on YOUR website!
.
The necessary and sufficient condition is

the discriminant of the quadratic equation is zero: d = b^2 - 4ac = 0, referring to the standard form of the quadratic equation ax^2 + bx + c = 0. In your case b= 2, c= 4, therefore the discriminant d = = 4 - 16a. The condition d= 0 gives you an equation 4 - 16a = 0, or 16a = 4, which implies a = = 0.25. It is your Answer. a = = 0.25.

Solved.

----------------
To get introductory knowledge on quadratic equations, see the lessons
    - Introduction into Quadratic Equations
    - PROOF of quadratic formula by completing the square
in this site.

Answer by Alan3354(69443)   (Show Source):
You can put this solution on YOUR website!
Quadratics always have 2 solutions.
Sometimes the 2 are equal.