Answer:
f(x)-g(x)=5x^3-17x^2+4 which appears as option A
Step-by-step explanation:
Simply subtract the function's expressions as shown below, and combine like terms to express the final result:
[tex]f(x)=7x^3-10x^2-5\\g(x)=2x^3+7x^2-9\\f(x)-g(x)=7x^3-10x^2-5-[2x^3+7x^2-9]\\f(x)-g(x)=7x^3-10x^2-5-2x^3-7x^2+9\\f(x)-g(x)=7x^3-2x^3-10x^2-7x^2-5+9\\f(x)-g(x)=5x^3-17x^2+4[/tex]