21i have seen it here probably..lets see if i can fetch the link..
If ax2 + bx + c = 0 be a quadratic equation where a,b and c are odd then prove that, it can't have a rational number solution.
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6 Answers
36@shubhodip b - just do this... in place of onclick = 'alert("hi..")' type this, <input type = 'button' value = 'any value u wanna put' onclick = 'alert("hi")'> :D I guess this will work... and thanks in advance...!!
21http://www.targetiit.com/iit-jee-forum/posts/02-08-10-no-rational-roots-17243.html
21ieasier way..( i am lazy ri8 now, but lets post it)
Its clear that we have to show b2-4ac ≠k2
assume b2- 4ac=k2
(b+k)(b-k) = 4ac
(b+k)/2 * (b-k)/2 = ac as 'a' and 'c' are odd
b+k/2 and (b-k)/2 must be odd
so (b+k)/2 + (b-k)/2 = odd + odd = even
or b= even
which contradicts that b is odd