# SAT Math Multiple Choice Question 917: Answer and Explanation

Home > SAT Test > SAT Math Multiple Choice Practice Tests

### Test Information

- Use your browser's back button to return to your test results.
- Do more SAT Math Multiple Choice Practice Tests.

**Question: 917**

**1.** Given the functions defined above, what is the value of (*g* ° *h*)(5)?

- A. 0
- B.
- C. 2
- D. Undefined

**Correct Answer:** D

**Explanation:**

**D**

**Difficulty:** Medium

**Category:** Passport to Advanced Math / Functions

**Strategic Advice:** The notation (*g* ° *h*)(*x*) indicates a composition of two functions, which can also be written as *g*(*h*(*x*)) and read as "*g* of *h* of *x.*" It means that the output when *x* is substituted in *h*(*x*) becomes the input for *g*(*x*). Just remember that when working with compositions, you always start with the function that is closest to *x*.

**Getting to the Answer:** Substitute 5 for *x* in *h*(*x*), simplify, and then substitute the result into *g*(*x*):

Be careful-a number divided by 0 is not 0! In fact, division by 0 is not defined, so (*g* ° *h*)(5) is undefined, which is (D).