因式分解唔識.........

a)
16x2 + 18x - 9
= (2x + 3)(8x - 3)



b)
Let x = 6y2 - 3

16(6y2 - 3)2 + 18(6y2 - 3) - 9
= 16x2 + 18x - 9
= (2x + 3)(8x - 3)
= [2(6y2 - 3) + 3][8(6y2 - 3) - 3]
= (12y2 - 6 + 3)(48y2 - 24 - 3)
= (12y2 - 3)(48y2 - 27)
= 3(4y2 - 1)•3(16y2 - 9)
= 9[(2y)2 - 1][(4y)2 - (3)2]
= 9(2y + 1)(2y - 1)(2y + 3)(2y - 3)
=

a)
16x^2+18x-9
= (8x-3)(2x+3)

b)
16(6y^2-3)+18(6y^2-3)-9
= (8(6y^2-3)-3)(2(6y^2-3)+3)
= (48y^2-27)(12y^2-3)