1. (3 -2c+1)(3+2c -1) ;2. (a+b+2)(a+b) -(a-b)² +1 =(a+b)² +2(a+b) -(a-b)² +1 = 2(a+b) +1 + (a+b)² -(a-b)² =2(a+b) +1 +4ab ???3. (x² +1)² - 4x² =(x² +1 -2x)(x² +1 +2x) =(x-1)²(x+1)² || (x² -1)² || (x² )² +2*x²*1 +1² - 4x² = (x² )² -2*x²*1 = (x² -1)² .4. 1 -(8a -3)² =(1 -8a+3)(1+8a - 3) =(4 - 8a)(8a -2) =8(1-2a)(4a -1).5. 25 +40a³ +16a⁶ =5² +2*5*4a³ +(4a³)² =(5 +4a³)² .