Find the Value of k for Which the Roots Are Real and Equal
Solution
Given: $$4x^2+kx+9=0$$
Here, $$a=4,\quad b=k,\quad c=9$$
For real and equal roots, $$D=b^2-4ac=0$$
$$k^2-4(4)(9)=0$$
$$k^2-144=0$$
$$k^2=144$$
$$k=\pm12$$
Answer
The value(s) of k for which the roots are real and equal is: $$\boxed{k=\pm12}$$