I believe the answer is 5t
6s7t-6s2t = 5t
Answer:
a) 1/27
b) 16
c) 1/8
Step-by-step explanation:
a) 
One of the properties of the exponents tells us that when we have a negative exponent we can express it in terms of its positive exponent by turning it into the denominator (and changing its sign), so we would have:

And now, solving for x = 9 we have:

b) 
This is already a positive rational exponent so we are just going to substitute the value of y = 8 into the expression

c) 
Using the same property we used in a) we have:

And now, solving for z = 16 we have:

Answer:
10√5 - 5√2
or
5(2√5 - √2)
Step-by-step explanation:
Given:
2√5(5 - 5√5)
Required:
Multiply and simplify
Solution:
2√5(5 - 5√5)
Apply distributive property by multiplying each term in the bracket by 2√5
2√5*5 - 2√5*5√5
2*5√5 - 2*5√5*√5
10√5 - 10√25
10√5 - 10*5
10√5 - 50
10√5 - (25*2)
10√5 - 5√2
Or
5(2√5 - √2)