(x-5)(x+5)
(6-y)(6+y)
(a-7)(a+7)
(1-c)(1+c)
(m-4)(m+4)
(n-2)(n+2)
(x-9)(9+?)
(11-d)(d +11)
(4+b)(b-4)
(a+12)(12-a)
(c-3)(3+c)
(8-b)(b+8)
(2x-3)(2x+3)
(4y-7)(4x+7)
(8a+5)(5-8a)
(9c-1)(1+9c)
(10+3d)(3d-10)
(11x-6)(6+11x)
(2m-0,7)(2m+0,7)
(1,2-5y)(1,2+5y)
(8n+0,6)(8n-0,6)
(0,9p+2)(0,9p-2)
(1,1d-8)(8+1,1d)
(0,1a+1)(1-0,1a)
(0,7x-3y)(0,7x+3y)
(1,3m-4n)(1,3m+4n)
(5a+0,4d)(0,4d-5a)
(2,5p+6q)(6q-2,5p)
(8c-2,1d)(2,1d+8c)
(0,9x+2y)(0,9x-2y)
(1/4a-0,9b)(1/4a+0,9b)
(2/5m-1,5n)(2/5m+1,5n)
(3/7x-1/2y)(3/7x+1/2y)
(4/9c-9/10d)(9/10d+4/9c)
(1/3a+6/7b)(6/7b-1/3a)
(1/4a-0,9b)(1/4a+0,9b)

(x-5)(x+5) = х? — 25
(6-y)(6+y) = 36 — y?
(a-7)(a+7) = a? — 49
(1-c)(1+c) = 1 — c?
(m-4)(m+4) = m? — 16
(n-2)(n+2) = n? — 4
(x-9)(9+?) = x? — 81
(11-d)(d +11) = 121 — d?
(4+b)(b-4) = b? — 16
(a+12)(12-a) = 144 — a?
(c-3)(3+c) = c? — 9
(8-b)(b+8) = 64 — b?
(2x-3)(2x+3) = 16x? — 9
(4y-7)(4y+7) = 16y? — 49
(8a+5)(5-8a) = 25 — 64a?
(9c-1)(1+9c) = 81c? — 1
(10+3d)(3d-10) = 9d? — 100
(11x-6)(6+11x) = 121x? — 36
(2m-0,7)(2m+0,7) = 4m? — 0,49
(1,2-5y)(1,2+5y) = 1,44 — 25y?
(8n+0,6)(8n-0,6) = 64n? — 0,36
(0,9p+2)(0,9p-2) = 0,81 — 4
(1,1d-8)(8+1,1d) = 1,21d? — 64
(0,1a+1)(1-0,1a) = 1 — 0,01a?
(0,7x-3y)(0,7x+3y) = 0,49x? — 9y?
(1,3m-4n)(1,3m+4n) = 1,69m? — 16n?
(5a+0,4d)(0,4d-5a) = 0,16d? — 25a?
(2,5p+6q)(6q-2,5p) = 36q? — 6,25p?
(8c-2,1d)(2,1d+8c) = 64c? — 4,41d?
(0,9x+2y)(0,9x-2y) = 0,81x? — 4y?
(1/4a-0,9b)(1/4a+0,9b) = 1/16a? — 0,81b?
(2/5m-1,5n)(2/5m+1,5n) = 4/25m? — 2,25n?
(3/7x-1/2y)(3/7x+1/2y) = 9/49x? — 1/4y?
(4/9c-9/10d)(9/10d+4/9c) = 16/81c? — 81/100d?
(1/3a+6/7b)(6/7b-1/3a) = 36/49b? — 1/9a?
(1/4a-0,9b)(1/4a+0,9b) = 1/16a? — 0,81b?

Но пунктов за такой список можно было и побольше дать.