Answer
$-y^{2}+4y-6$
Work Step by Step
Write out equation:
$(5y^{2}-6y-4)-2(3y^{2}-5y+1)$
Distribute the $2$ over $(3y^{2}-5y+1)$:
$(5y^{2}-6y-4)-(6y^{2}-10y+2)$
Distribute the $-1$ over $6y^{2}-10y+2)$ (you can drop both sets of parentheses after this step):
$5y^{2}-6y-4-6y^{2}+10y-2$
Combine like terms:
$-y^{2}+4y-6$
