227k views
11 votes
If f(x) = x3+ x2and g(x) = x4+ x2+ x, what is the value of f(x) –g(x) when x = 1?

A) -2
B) -1
C) 1
D) 5

User Oria
by
5.8k points

1 Answer

9 votes

Answer:

B) -1

Explanation:


f(x)=x^3+x^2\\\\g(x)=x^4+x^2+x

METHOD 1


f(x)-g(x)=(x^3+x^2)-(x^4+x^2+x)=x^3+x^2-x^4-x^2-x\\\\=-x^4+x^3-x\\\\x=1\\\\-1^4+1^3-1=-1+1-1=-1

METHOD 2


x=1\\\\f(1)=1^3+1^2=1+1=2\\\\g(1)=1^4+1^2+1=1+1+1=3\\\\f(1)-g(1)=2-3=-1

User Shubhang B
by
5.9k points