Exercise 4.2 (PCTB)

1. Factorize each of the following expressions: (i) \( 4x^4 + 81y^4 \) \[(2x^2)^2 + (9y^2)^2 + 2(2x^2)(9y^2) – 2(2x^2)(9y^2)\] \[(2x^2 + 9y^2)^2 – 36x^2y^2\] \[(2x^2 + 9y^2)^2 – (6xy)^2\] \[(2x^2 + 9y^2 + 6xy)(2x^2 + 9y^2 – 6xy)\] (ii) \( a^4 + 64b^4 \) \[(a^2)^2 + (8b^2)^2 + 2(a^2)(8b^2) – 2(a^2)(8b^2)\] \[(a^2 + 8b^2)^2…