(adsbygoogle = window.adsbygoogle || []).push({}); 1.

(a) If the roots of the equation 2(x)^2 + kx + 100 = 0 are positive,

find the possible range of k.

(b) If, in addition, one root is twice the other, find the roots and the value of k.

I have tried (a), but incorrect:

discriminate > 0

k^2 - (4)(2)(100) > 0

k^2 > 800

k > + or - 20(2)^1/2

What's wrong with my calculation?

The correct ans is:k is less than or equal to - 20 (2)^1/2

2. Find the values of t for which the quadratic equation

(x)^2 - tx + t + 3 = 0 has one positive root and one negative root.

>>> I have no idea to start doing it.

The correct answer is t < -3

Can anyone help?

Wish you all have a Merry Christmas! :rofl:

**Physics Forums | Science Articles, Homework Help, Discussion**

Dismiss Notice

Join Physics Forums Today!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

# Homework Help: Quadratic Inequalities

**Physics Forums | Science Articles, Homework Help, Discussion**