1. 5x²-45 2. ax²-4a. 3. 3x²-75a² 4. -2ay²+2a³ 5. 5a²+10ab+5b² 6. ax²-2axy+ay² 7. -6a²+12ab-6b²

1. 5(х^2-9)=5(х-3)(х+3)
2. а(х^2-4)=а(х-2)(х+2)
3. 3(х^2-25а^2)=3(х-5а)(х+5а)
4. 2a(-y^2+a^2)=2a(a-y)(a+y)
5. 10ab+(5a^2-5b^2)=10ab+5(a-b)(a+b)
6. a(x^2-2xy+y^2)=a(x-y)^2
7. 12ab+(-6a^2-6b^2)=12ab-6(a^2-b^2)=12ab-6(a+b)(a-b)