how do you work this out?

Question

Find the domain: f(x)= 3/x+1

a. (-infinite,-3)
b. (-infinite,-1)U(-1,infinite)
c. (-infinite,-3)U(-3,infinite)
d. (-infinite,-1)

Answer 1

The answer is B, assuming you meant 3/(x+1).

The only restriction is on the denominator, in that it cannot be equal to 0 due to the division by zero property.

x+1=0 when x = -1. Therefore x is not equal to -1 but could be anything else.

Answer 2

x can be any value except 0, except if you meant:
f(x) = 3/(x+1). If this is what you meant, the x can take on any value except -1. In this case the answer would be b (-infinite,-1)U(-1,infinite).

Answer 3

if you meant f(x) = 3/x + 1:
the function f(x) is not defined for x = 0, so a correct domain would be one not containing 0, so A and D are correct

if you meant f(x) = 3/(x+1) then the function is not defined for -1
so the correct answer is A,B or D because those domains don't contain x = -1

Answer 4

You need some paranthesis to remove your ambiguity.

(3/x) + 1
or
3/(x+1)

are very different animals.

Answer 5

b