Question

9m2-6/5m+c is a perfect square what is the value of c

Answer 1

The expression given to us is:

$9m^2-\frac{6}{5}m+c$

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:

$-\frac{6}{5}m=2\times 3m\times \sqrt{c}$

$\therefore \sqrt{c}=-\frac{1}{5}$

Thus, $c=\frac{1}{25}$

Thus, for 9m^2-(6/5)m+c to be a perfect square, the value of c must be equal to $\frac{1}{25}$ or 1/25

Answer 2

I think it is right too!