Question

If f(x)=5x-2 and g(x)=2x+1, find (f+g)(x) A.4x-3 B.3x-1 C.7x-3 D.7x-1

Answer 1

Choice D: 7x - 1

Explanation:

We are given the following functions

f(x) = 5x - 2

g(x) = 2x + 1

(f+g)(x) is nothing but f(x) + g(x)

So (f + g)(x) = (5x - 2) + (2x + 1)

= 5x - 2 +2x + 1

= 5x + 2x - 2 + 1

= 7x - 1

Answer: Choice D: 7x - 1

Answer 2

(f+g)(x) = 7x - 1

Explanation:

(f+g)(x) is basically f(x) + g(x). Substitute f(x) and g(x) in:

`\displaystyle{\left(f+g\right)(x)=f(x)+g(x)}\\\\\displaystyle{f(x)+g(x) = \left(5x-2\right)+\left(2x+1\right)}\\\\\displaystyle{f(x)+g(x)=5x-2+2x+1}\\\\\displaystyle{f(x)+g(x)=7x-1}`

Therefore, (f+g)(x) = 7x - 1