Given the equation:
[tex]f(x)=(-x)^3-x^2-x+15[/tex]To find f(-5), substitute x by -5 and solve the equation.
[tex]f(-5)=[-(-5)\rbrack^3-(-5)^2-(-5)+15[/tex]To solve it, first, solve the signs and the exponents.
[tex]\begin{gathered} f(-5)=5^3-(-5)^2+5+15 \\ f(-5)=125-25+20 \\ f(-5)=120 \end{gathered}[/tex]Answer: f(-5) = 120.
