Question

can someone please explain these to me? My book makes this sooo complicated!

f(x)= 2x^3-5x; g(x)=x^2+8x+15

what is the first step?

Answer 1

what is the question?

Answer 2

Find f + g and its domain.

Answer 3

Just add f(x) and g(x)

Answer 4

oh! 2x^3 + x ^2+ 3x + 15

Answer 5

yes

Answer 6

the domain of the combination has to be evaluated by itself.

there are norestriction for values which x can be, so the domain of (f+g)(x) = (-infinity, infinity)

Answer 7

yay are there any restrictions or how can you tell if there is a restriction?

Answer 8

Domain is all x values that are allowed.
If a value of x would make f(x) undefined then that x value should be excluded.
For example, f(x) = 1 / (x - 2) is not defined when x = 2.
So the domain should exclude x = 2.

Answer 9

got it =) thank you

Answer 10

you are welcome.

Answer 11

if the next thing they ask me for is f-g do I just switch the positive signs to negative?