[tex]10.\\\\ a)9y^2-(x^2-8x+16)=9y^2-(x-4)^2=\\
(aplicam~ a^2-b^2=(a-b)(a+b) ) \\
=(3y-x+4)(3y+x-4)\\\\ b)(x^2-2x+1) - 4y^2 =(x-1)^2 - (2y)^2=\\
=(x-1-2y)(x-1+2y) \\\\ c) 9y^2 - (x^2-8x+16) = (3y)^2 - (x-4)^2=\\
=(3y-x+4)(3y+x-4)\\\\
[/tex]
[tex]\\\\ d) 36 x^2+12x+1-49y^2 = (6x+1)^2-49y^2\\=(6x+1+7y)(6x+1-7y)\\\\ e)x^2-12x+36-y^2-8y-16 = (x-6)^2-(y+4)^2\\
=(x-6-y-4)(x-6+y+4)=(x-10-y)(x+2+y)\\\\ f) x^2+14xy+49y^2-a^2-6ab-9b^2 = (x+7y)^2-(a+3b)^2\\=(x+7y-a-3b)(x+7y+a+3b) \\\\ g)(9x^2-6x+1)-(4x^2+12x+9) = (3x-1)^2-(2x+3)^2\\=(3x-1-2x-3)(3x-1+2x+3)=(x-4)(5x+2)\\\\ g) (16x^2+8x+1)-(9x^2-12x+4)=(4x+1)^2-(3x-2)^2\\=(4x+1-3x+2)(4x+1+3x-2)
=(x+3)(7x-1)[/tex]