SOLUTION: <pre><b>if ax²+bx+c=0, where a, b, and c are integers and its two solutions have to be rational numbers, then b^2-4ac=?</pre>

Algebra ->  Expressions-with-variables -> SOLUTION: <pre><b>if ax²+bx+c=0, where a, b, and c are integers and its two solutions have to be rational numbers, then b^2-4ac=?</pre>      Log On


   

Question 49295: 
if ax²+bx+c=0, where a, b, and c are integers 
and its two solutions have to be rational numbers,
then b^2-4ac=?
Answer by AnlytcPhil(1806) About Me  (Show Source):
You can put this solution on YOUR website!
if ax²+bx+c=0, where a, b, and c are integers 
and its two solutions have to be rational numbers,
then b^2-4ac=?

(1)3 (2)6 (3) 36 (4) 63
and please show me how you got the answer

The quadratic formula is

                  ______ 
            -b ± Öb²-4ac
        x = —————————————
                2a 

which gives the solutions to ax²+bx+c = 0

The values will be rational only if what's under the square root radical,
namely the discriminant b²-4ac, is a perfect square.  

Edwin