Solve the problem.With the function f(x) = logax, why can't x be less than 0?

Question

What will be an ideal response?

Answer 1

Answers may vary. One possibility: The function is defined for all positive numbers a,  Since a positive number raised to any real-number exponent is a positive number, x must be positive, too. That begs the question of why a must be positive. Assume that a is a negative number. A negative number raised to certain powers (e.g., 1/2) would yield a non-real number.