Given the functions:
[tex]f(x)=x^2+17x+72[/tex][tex]g(x)=x+9[/tex]You have to subtract the functions:
[tex]f(x)-g(x)[/tex][tex](x^2+17x+72)-(x+9)[/tex]Note that I wrote both functions in parentheses separated by the minus sign. For the seconf term, the minus sign is as if the parenthesis is being multiplied by -1, the sign of both x and 9 is inverted:
[tex]x^2+17x+72-x-9[/tex]Order the like terms
[tex]x^2+17x-x+72-9[/tex]And simplify
[tex]x^2+16x+63[/tex]So the result in standard form is
[tex]f(x)-g(x)=x^2+16x+63[/tex]