Given the function f (x) = 3x, find the value of f-1 (81).
For this case, the first thing you should do is rewrite the function.
We have then:
y = 3 ^ x
From here, we clear the value of x:
log3 (y) = log3 (3 ^ x)
log3 (y) = x
Then, we rewrite the function again:
f (x) ^ - 1 = log3 (x)
Now, we evaluate the inverse function for x = 81:
f (81) ^ - 1 = log3 (81)
f (x) ^ - 1 = 4
Answer:
the value of f-1 (81) is:
f (x) ^ - 1 = 4
I think b or d are answer ...
Answer:
$20
Step-by-step explanation:
Paul is making bread using a recipe. The amount of flour he uses is proportional to the number of loaves of bread. He uses 11 1/4 cups of flour to make 5 loaves of bread. If Paul used 18 cups of flour, and then sold the loaves of bread he made at a bake sale for $2.50 each, how much money would Paul make from his bread sales?
Step 1
Find out how many loaves of bread he can produce from 18 cups of flour
11 1/4 cups of flour = 5 loaves of bread
18 cups of flour = x loaves of bread
Cross Multiply
11 1/4 cups × x loaves = 18 cups × 5 loaves
x loaves = 18 cups × 5 loaves/ 11 1/4 cups
x loaves = 90 ÷ 11 1/4
x loaves = 90 ÷ 45/4
x loaves = 90 × 4/45
x loaves = 8 loaves of bread
He can produce 8 loaves of bread from 18 cups of flour.
Step 2
We are told that:
1 loaf of bread costs $2.50
Hence,
1 loaf of bread = $2.50
8 loaves of bread = $x
Cross Multiply
$x = 8 loaves of bread × $2.50
$x = $20
Therefore, Paul made $20 from his bread sales
512.50/125%=410
100% is the dealers cost
25% is the markup
$410 is the dealer's price before markup
410×25%=102.5. 410+102.5=512.5
