DSST Mathematics 4

Question 1

What is the domain of f(x) = √(x² - 9)?

Accepted Answer

x ≤ -3 or x ≥ 3

Answer

We need x² - 9 ≥ 0, so x² ≥ 9, giving x ≤ -3 or x ≥ 3.

Question 2

A car travels 150 miles in 2.5 hours. What is its average speed in miles per hour?

Accepted Answer

60 mph

Answer

Average speed = distance / time = 150 / 2.5 = 60 mph.

Question 3

What is the 10th term of the arithmetic sequence 3, 7, 11, 15, ...?

Accepted Answer

39

Answer

The common difference is 4; aₙ = 3 + (n-1)·4 = 3 + 9·4 = 39.

Question 4

If f(x) = 2x + 1 and g(x) = x², what is f(g(3))?

Accepted Answer

19

Answer

g(3) = 9, then f(9) = 2(9) + 1 = 19.

Question 5

Which of the following is equivalent to (x² - 4) / (x - 2) for x ≠ 2?

Accepted Answer

x + 2

Answer

x² - 4 factors as (x-2)(x+2), so the expression simplifies to x + 2.

DSST - DANTES Subject Standardized Tests Practice Test