Algebra

1)

$(a+3b)^2-[(2a-b)^2-(3a-5b)(3a+5b)-6a(a-2b)]-2(5a^2-6b^2-ab)$

2)  $(x-2y)^3+[-y^2(2x-y)+(2x+y)^3]-[(x+2y)(2x^2-xy+3y^2)-3y^2(4y-5x)]$

$(x^3−6x^2y+12xy^2−8y^3)$+$[(−2xy^2+y^3)+(8x^3+12x^2y+6xy^2+y^3)]$−$[(x+2y)⋅(2x^2−xy+3y^2)$−$(−15xy^2+12y^3)]$

$(x^3−6x^2y+12xy^2−8y^3)$+$[8x^3+12x^2y+4xy^2+2y^3]$−$[(2x^3+3x^2y+xy^2+6y^3)$−$(−15xy^2+12y^3)]$

$(9x^3+6x^2y+16xy^2−6y^3)$−$[2x^3+3x^2y+16xy^2−6y^3]$

$7x^3+3x2y$

3) $(3a-2b)(3a+2b)-(6a^3b-4ab^3):(-2ab)-6(a+b)(a-b)$