1)8x-6+20 -15x - 2 x +16 = 39
8x-15x-2x=6-20-16+39
9x=9
x=1
2) 18x-45-12x+28+2x-3=20
18x-12x+2x=45-28+3+20
8x=40
x=5
1) 3a^3-6a^2+3a-2a^3+10a^2-12a=
=a^3+4a^2-9a=a(a^2+4a-9)
2) 7b^3-7b^2+14b-3b^3-6b^2+9b=
=4b^3-13b^2+23b=b(4b^2-13b+23)
3) 15c^3-10c^2+25c-4c^3+c^2-c=
=11c^3-9c^2+24c=c(11c^2-9c+24)
4) 20x^3-60x^2+70x+2x^3-10x^2+6x=
=18x^3-75x^2+76x=x(18x^2-75x+76)