Answer:
1.896
Step-by-step explanation:
You can answer this just using your number sense.
[tex]\log_7{(40)}\approx 1.896[/tex]
You know that 49 = 7², so log₇(49) = 2. The log function has a fairly small slope, so log₇(40) will not be far from 2.
_____
If you want to use your calculator, you can use the "change of base formula".
log₇(49) = log(49)/log(7) ≈ 1.602060/0.845098 ≈ 1.896
