difficult SAT practice problems

[Fallingdownx93]

My Pre-Calc/Trig teacher gave my class a packet of SAT practice problems... I don't think they're really going to be on the SAT because I can't even figure them out. There are several. Help would be greatly appreciated

1. If X/(X^15) = 8X^-1, and x > 0, then X =
a. square root of 2/4
b. 2/square root of 2
c. 4
d. 16
e. 64

2. If 10^X = 64, what is the value of 10^ (X/2+1)?
a. 18
b. 42
c. 80
d. 81
e. 320

3. If y^2 - y = 0, 7^(4X-3) = y, and y is a positive integer, what is the value of X?

4. What is the value of (b^0-b^2/b^0+b)^(-1/2) when b = 3/4 ?

5. If the square root of x times the cubed root of x times the k root of x = x, then what is the value of k?

6. What is the value of x if 8^(x/3) = 16^(y+8) and 5^(x+y) = 125^(X-5)?

 

[Deleted member 4993]

My Pre-Calc/Trig teacher gave my class a packet of SAT practice problems... I don't think they're really going to be on the SAT because I can't even figure them out. There are several. Help would be greatly appreciated

These are SAT problems:
1. If X/(X^15) = 8X^-1, and x > 0, then X =

Use laws of exponents

\(\displaystyle \frac{a^m}{a^n} = a^{m-n}\)
a. square root of 2/4
b. 2/square root of 2
c. 4
d. 16
e. 64

2. If 10^X = 64, what is the value of 10^ (X/2+1)?

First find 10^(x/2) = ??

then find 10^(x/2+1) = 10 * 10^(x/2) = ??

a. 18
b. 42
c. 80
d. 81
e. 320

3. If y^2 - y = 0, 7^(4X-3) = y, and y is a positive integer, what is the value of X?

y^2 - y = 0 >>>> y = 1 and go from there....

4. What is the value of (b^0-b^2/b^0+b)^(-1/2) when b = 3/4 ? ..... use b^0 = 1 and then factorize.

5. If the square root of x times the cubed root of x times the k root of x = x, then what is the value of k?

6. What is the value of x if 8^(x/3) = 16^(y+8) and 5^(x+y) = 125^(X-5)?