If h(x)=(f+g)(x), f(x)=5x+2h(x)=(f+g)(x),f(x)=5x+2 how do you determine g(x) given h(x)=x^2+5x+2h(x)=x2+5x+2?

1 Answer
May 16, 2018

g(x) = x^2 g(x)=x2

Explanation:

We have:

h(x)=(f+g)(x), f(x)=5x+2h(x)=(f+g)(x),f(x)=5x+2

and we seek g(x)g(x) given h(x)=x^2+5x+2h(x)=x2+5x+2

We can write

h(x) = (f+g)(x) h(x)=(f+g)(x)
\ \ \ \ \ \ \ = f(x)+g(x)

So using f(x)=5x+2 and h(x)=x^2+5x+2, then:

h(x) = f(x)+g(x) => x^2+5x+2 = 5x+2 + g(x)

So then:

g(x) = (x^2+5x+2) - (5x+2)
\ \ \ \ \ \ \ = x^2+5x+2 - 5x-2
\ \ \ \ \ \ \ = x^2