tkaye
18

# expand and simplify the following expression: $(a-2b){3}$

$(x-y)^3=x^3-3x^2y+3xy^2-y^3\\--------------------------\\(a-2b)^3=a^3-3a^2\cdot2b+3a\cdot(2b)^2-(2b)^3\\\\=a^3-6a^2b+12ab^2-8b^3$