11:10am
20 minutes before 12 noon is 11:40am
30 minutes before 11:40am is 11:10am
Answer:
x = 10
Step-by-step explanation:
Using the rules of logarithms
• log x + log y ⇔ log(xy)
• log
⇔ n log x
• log x = log y ⇒ x = y
Given
ln20 + ln5 = 2 lnx , then
ln(20 × 5) = ln
ln 100 = ln
, hence
x² = 100 ( take the square root of both sides )
x = 10
We are given f(x) = 5x
and we are to find inverse of f(x).
Step 1:
Replace f(x) by y.
So,
y = 5x
Step 2:
Isolate x
So,
x = y/5
Step 3:
Replace x by f'(y)
So,
f'(y) = y/5
Step 4:
Replace all occurrences of y by x.
So,
f'(x) = x/5
Therefore, the inverse of f(x) = 5x is f'(x) = x/5