+0  
 
0
196
1
avatar

Determine whether the conjecture below is sometimes, always, or never true. Explain. 

 

In a quadratic in standard form, if a and c are different signs, then the solutions will be real. 

Guest Dec 3, 2017

Best Answer 

 #1
avatar+2248 
+2

Let's consider the discriminant of a quadratic, \(b^2-4ac\)

 

If and are opposite signs, then ac will be negative. -4ac will be positive, then. bwill also be positive--no matter whether b is positive or negative. This means that b2-4ac represents the addition of positive values, which will never be negative. Hence, the discriminant will always be positive, so the solutions can never be imaginary. This conjecture is always true.

TheXSquaredFactor  Dec 3, 2017
 #1
avatar+2248 
+2
Best Answer

Let's consider the discriminant of a quadratic, \(b^2-4ac\)

 

If and are opposite signs, then ac will be negative. -4ac will be positive, then. bwill also be positive--no matter whether b is positive or negative. This means that b2-4ac represents the addition of positive values, which will never be negative. Hence, the discriminant will always be positive, so the solutions can never be imaginary. This conjecture is always true.

TheXSquaredFactor  Dec 3, 2017

22 Online Users

avatar
avatar

New Privacy Policy

We use cookies to personalise content and advertisements and to analyse access to our website. Furthermore, our partners for online advertising receive information about your use of our website.
For more information: our cookie policy and privacy policy.