If there is exactly one root of the equation x^2 + ax + 2b, where a and b are positive constants, what is b in terms of a?  Choose the correct choice from the following
A) a/2
B) a
C) 3a/2
D) a^2/2
E) a^2/8
one root for a quadratic equation ax^2+bx+c is possible only when b^2 = 4ac ---1   Here b = a   c= 2b   a = 1   substituting these values in 1, we have   a^2 = 8b =&gt; b =a^2/8   Answer is a^2/8.
<result>E</result>
If there is exactly one root of the equation x^2 + ax + 2b, where a and b are positive constants, what is b in terms of a?