Which statement correctly describes the domain of the expression (blah/(x+blah))^20?

• A. The expression is defined for all real x and blah.
• B. x ≠ -blah
• C. blah ≠ 0
• D. x ≠ 0

Answer: (B)

The domain is determined by where the expression is defined. The only potential issue comes from the denominator x + blah. As long as x + blah ≠ 0, the fraction is defined. Raising the base to the 20th power doesn’t add any new restrictions because an even positive integer power is defined for any real base. Therefore, the only restriction is x ≠ -blah, and the expression is defined for all real x except when x equals negative blah.