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:
4(5j+3j) is 32j
4(3j) is 12j
5j+3j+9j is 17j
Step-by-step explanation:
Find how much each earns
pres =6 and 3/4 times mec pay=17.25 times 6.75=116.4375, about $116.44
janitor is 3/4 or 0.75 of janitor=17.25 times 0.75=12.9375, about $12.94
add them
$17.25+$116.4275+$12.9375=146.615
round
$146.62