Answer:
x^4 -x^3 -4x^2-3
Step-by-step explanation:
f(x)=x^4−x^2+9
g(x)=x^3+3x^2+12
(f−g)(x)= x^4−x^2+9 - (x^3+3x^2+12)
Distribute the minus sign
(f−g)(x)= x^4−x^2+9 - x^3-3x^2-12
I like to line them up vertically
x^4 −x^2+9
- x^3 -3x^2-12
---------------------------
x^4 -x^3 -4x^2-3
