1)
а) 3x² -12 =3(x² - 4)=3(x-2)(x+2).
б) 50b - 2a²b =2b(5² -a²) =2b(5 - a)(5+a).
в) -3a³ +3ab² = -3a(a² -b²) = -3a(a-b)(a+b).
г) a³c -ac³ =ac(a² -c²) =ac²(a-c)(a+c).
2)
а) 3x² -6xy +3y² =3(x² -2xy+y²) = 3(x - y)².
б) -a² +10ab -25b² = -(a² - 2*x*5b +(5b)²) = -(x - 5b)².