Answer:
[tex]-439[/tex]
Step-by-step explanation:
we have
[tex]s(x)=2-x^{2}[/tex]
[tex]t(x)=3x[/tex]
we know that
[tex](sot)(x)=2-(3x)^{2}[/tex]
[tex](sot)(x)=2-9x^{2}[/tex]
For x=-7
substitute
[tex](sot)(-7)=2-9(-7)^{2}[/tex]
[tex](sot)(-7)=2-441[/tex]
[tex](sot)(-7)=-439[/tex]
