What is the domain of the composite function G(F(x))?

F(x)=x+4, G(y)= 1/y

G(F(x))= 1/x+4

A. x4
B. X greater than or equal to 4
C. All real numbers
D. All real numbers except -4

Question

What is the domain of the composite function G(F(x))? 

F(x)=x+4, G(y)= 1/y

G(F(x))= 1/x+4

A. x>4
B. X greater than or equal to 4
C. All real numbers 
D. All real numbers except -4

anonymous · Answer

@zepdrix Can you help me please?

anonymous · Answer

B is wrong it is B. x less than or equal to 4

zepdrix · Answer

In the land of math,
we're not allowed to divide by 0.
Denominator = 0 bad bad bad bad bad.

zepdrix · Answer

What values of x make that happen in our composite function?

zepdrix · Answer

x+4 is in the bottom,
what value of x turns that expression into 0?

anonymous · Answer

I'm not for sure..... By switching terms?

zepdrix · Answer

Let's `allow` this denominator to equal zero,
and then solve for x to figure what the "bad value" is.

anonymous · Answer

Ok,

zepdrix · Answer

$$\large\rm x+4=0$$Solve for x.
What do we do? Subtract 4 from each side I guess?

anonymous · Answer

Yes, that is right,

zepdrix · Answer

Ok so do it! :D lol
solve for x.

anonymous · Answer

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