Answer
$\color{blue}{y^6-18y^2+8y}$
Work Step by Step
Distribute $2$ to obtain:
$=2(3y^6)-2(9y^2)+2(2y)-(5y^6-4y)
\\=6y^6-18y^2+4y-(5y^6-4y)$
Subtract each term of the binomial to obtain:
$=6y^6-18y^2+4y-5y^6-(-4y)
\\=6y^6-18y^2+4y-5y^6+4y$
Combine like terms to obtain:
$=(6y^6-5y^6)-18y^2+(4y+4y)
\\=(6-5)y^6-18y^2+(4+4)y
\\=\color{blue}{y^6-18y^2+8y}$
