(x-4)^2-6
(x-4)(x-4)-6
x^2-4x-4x+16-6
x^2-8x+10
----------------------------
10a+(a-5)(a-5)
10a+a^2-5a-5a+25
a^2+25
----------------------
(3m-7n)(3m-7n)
3m^2-21mn-21mn+49n^2
3m^2-41mn+49n^2
-----------------------
(6a-3b)(6a-3b)
6a^2-18ab+3b^2
----------------------
b(b-3)-(b-4)(b-4)
b^2-3b-b^2-4b-4b+16
b^2-3b-b^2-8b+16
-3b-8b+16
-11b+16