The expression given to us is:
[tex] 9m^2-\frac{6}{5}m+c [/tex]
If the above expression is a perfect square then the middle term will have to be 2 times the square root of the first term times the square root of the last term. Thus:
[tex] -\frac{6}{5}m=2\times 3m\times \sqrt{c} [/tex]
[tex] \therefore \sqrt{c}=-\frac{1}{5} [/tex]
Thus, [tex] c=\frac{1}{25} [/tex]
Thus, for 9m^2-(6/5)m+c to be a perfect square, the value of c must be equal to [tex] \frac{1}{25} [/tex] or 1/25
