(ax+by)^2-(bx+ay)^2 (ar + by + br + ay)(ar + by- br - ay) 4. 1-26a^2+25a^2 =(a^2-25)(a^2-1) =(a+5)(a-5)(a+1)(a-1) 5. (x+y)^2-1(x+y-1) =(x+y)^2-1(x+y)+1 =[(x+y)-2][(x+y)-2] =(x+y-2)^2 6. (a2+a+1)2+2...