Factor using suitable identities:

(A) $16y^2 - 24y + 9$

(B) $\frac{9}{4}s^2 + 6st + 4t^2$

(C) $\frac{m^2}{9} + \frac{mk}{3} + \frac{k^2}{4} + 3nk + 2mn + 9n^2$

(D) $\frac{p^2}{16} - 2 + \frac{16}{p^2}$

(E) $9a^2 + 4b^2 + c^2 - 12ab + 6ac - 4bc$                                                [Page No. 77]

(A) $16y^2 - 24y + 9 = (4y)^2 - 2(4y)(3) + 3^2 = (4y - 3)^2$

(B) $\frac{9}{4}s^2 + 6st + 4t^2 = \left(\frac{3s}{2}\right)^2 + 2\left(\frac{3s}{2}\right)(2t) + (2t)^2 = \left(\frac{3s}{2} + 2t\right)^2$

(C)$$\left( \frac{m}{3} \right)^2 + \left( \frac{k}{2} \right)^2 + (3n)^2 + 2\left( \frac{m}{3} \right)\left( \frac{k}{2} \right) + 2\left( \frac{k}{2} \right)(3n) + 2\left( \frac{m}{3} \right)(3n) = \left( \frac{m}{3} + \frac{k}{2} + 3n \right)^2$$

(D) $\left(\frac{p}{4}\right)^2 - 2\left(\frac{p}{4}\right)\left(\frac{4}{p}\right) + \left(\frac{4}{p}\right)^2 = \left(\frac{p}{4} - \frac{4}{p}\right)^2$

(E) $(3a)^2 + (-2b)^2 + c^2 + 2(3a)(-2b) + 2(-2b)(c) + 2(3a)(c) = (3a - 2b + c)^2$