Question 8
Indices25x − 5x − 20 = 0, find x
- A.1
- B.3
- C.5
- D.7
Show the answer and explanation
Answer: A (1)
Explanation
Let p = 5ˣ: p² − p − 20 = (p − 5)(p + 4) = 0. Since 5ˣ > 0, p = 5 and x = 1.
25x − 5x − 20 = 0, find x
Answer: A (1)
Let p = 5ˣ: p² − p − 20 = (p − 5)(p + 4) = 0. Since 5ˣ > 0, p = 5 and x = 1.