1.
2x^5-18x^3+14x
3y^2-14y+8
30b^2-16bc-32c^2
a^3+a^2+6a-2a^2-2a-12=a^3-a^2+4a-12
2.
3b(5a-b)
4a^4(1+6a^2)
(x-5)×(3x-2)
(m-n)(14+2x)
3.
5x(x-3)=0
x(x-3)=0
x=0
x-3=0, x=3
