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(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:

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# Quadratic Inequalities

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