Question

solve and simplify
3. (y^2-7y-5)-(-3y^2+3y-4)

Answer 1

$(y^2-7y-5)-(-3y^2+3y-4)=y^2-7y-5-(-3y^2)-3y-(-4)\\\\=y^2-7y-5+3y^2-3y+4$

combine like terms

$=(y^2+3y^2)+(-7y-3y)+(-5+4)=\boxed{4y^2-10y-1}$