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The number of non-negative integer values of k for which the quadratic equation $$x^{2}-5x+k=0$$ has only integer roots, is
Correct Answer: 3
The given quadratic equation is $$x^2-5x+k=0$$
Now, discriminant $$D=5^2-4k=25-4k$$
Now, it is given the equation must have integer roots.
So, $$25-4k$$ has to be a perfect square.
We need to find non-negative integer values of $$k$$
Now, for $$k=0$$, $$D=25-4\times\ 0=25$$, is a perfect square
For $$k=4$$, $$D=25-4\times4=25-16=9$$, is a perfect square
For $$k=6$$, $$D=25-4\times\ 6=1$$, is a perfect square
So, there are three non negative integer values of $$k$$.
So, correct answer is $$3$$.
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