Part 1!

i really, really need on this 50 ! will give the brainliest to correct ! nth term

look at the picture!

if you don't answer with correct answers or give something absurd or don't give enough details, your answer will be reported and deleted and you will lose the points for this !

1.  We have to find the fifth term of f(n) = 7 - 4(n - 1). 
That means x = 5. Substitute 5 into the equation for x. 
f(n) = 7 - 4(5 - 1) 
Subtract 5 - 1. 
f(n) = 7 - 4(4) 
Multiply 4 by 4. 
f(n) = 7 - 16 
Subtract 16 from 7. 
f(n) = -9 
The answer is D. 

2. Since we have to find the first 4 terms, we have to solve for x = 1, 2, 3, & 4. 
Multiply 1, 2, 3, and 4 by 6. We now have: 
f(x) = 6 - 25   f(x) = 12 - 25   f(x) = 18 - 25   f(x) = 24 - 25 
Subtract 25 from the first term: 6, 12, 18, and 24. 
f(x) = -19   f(x) = -13   f(x) = -7   f(x) = -1 
The answer is C. 

3. Now, we have to find the first 3 terms of f(x) = 10(2)^x.  So x is 1, 2, & 3. 
Raise 2 to the powers of 1, 2, and 3. The equations are now: 
f(x) = 10(2)   f(x) = 10(4)   f(x) = 10(8) 
Then multiply 10 by the three terms: 2, 4, and 8. 
f(x) = 20   f(x) = 40   f(x) = 80 
The answer is A. 

4. Find the 21st term of f(n) = 2 + 9(n - 1). Substitute 21 for n. 
f(n) = 2 + 9(21 - 1) 
Subtract 1 from 21. 
f(n) = 2 + 9(20) 
Multiply 9 by 20. 
f(n) = 2 + 180
Add 2 to 180. 
f(n) = 182 
The answer is B. 

5. Which sequence is described by f(n) = 2(3)^x-5. 
This is the only one which I'm not sure how to solve. Since I don't know, I won't answer it because I don't want to give you the wrong answer to the question, sorry about that. 

6. The ninth term in f(n) = 384(1/2)^n-1. Put 9 in for n & subtract 1 from 9. 
f(n) = 384(1/2)^8 
Raise 1/2 to the power of 8.
f(n) = 384(1/256) 
Multiply 1/256 by 384. 
f(n) = 384/256 
Reduce the fraction & make it a mixed number. 
f(n) = 1 1/2 

Hope this helped!