1. ## Need help

Need help with 11)，12）

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2. ## Re: Need help

Originally Posted by kokshen3414
Need help with 11)，12）
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Do not ever post the same question twice.
The quadratic $ax^2+bx+c=0$ has two real roots if and only if $b^2-4ac>0$.
That is the idea for both 11 & 12.