Answer:
[tex]\huge\boxed{h(g(y^2))=-3y^4-5y^2-5}[/tex]
Step-by-step explanation:
[tex]h(t)=t-5\\\\g(t)=-3t^2-5t\\\\g(y^2)\to\text{substitute}\ t=y^2\\\\g(y^2)=-3(y^2)^2-5y^2=-3y^4-5y^2\\\\h(g(y^2))\to\text{substitute in}\ h(t)\ t=-3y^4-5y^2\\\\h(g(y^2))=-3y^4-5y^2-5[/tex]