中等MATH-EXPL-010
Solve log_2 (x − 1) = 3.
A. 8
B. 7
C. 9✓ 答案
D. 10
解說
The equation means x − 1 = 2^3 = 8, so x = 9. The value 8 is the argument, not the solution. The argument x − 1 is positive, so x = 9 is allowed.
The equation means x − 1 = 2^3 = 8, so x = 9. The value 8 is the argument, not the solution. The argument x − 1 is positive, so x = 9 is allowed.