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:
If Larissa earns $500 per week, she will need $250 more in order to reach $750
Answer:
3/4
Step-by-step explanation:
You can simplify it by looking for what divides into both numbers. The lowest possible number is 3 because it can go into both 9 and 12.
9/3=3
12/3=4
3/4
X1=2-Square root 5 x2=2+ Square root 5
Step 1: Line up the equations so that the variables are lined up vertically.
Step 2: Choose the easiest variable to eliminate and multiply both equations by different numbers so that the coefficients of that variable are the same.
Step 3: Subtract the two equations.
Step 4: Solve the one variable system.
Step 5: Put that value back into either equation to find the other equation.
Step 6: Reread the question and plug your answers back in to check.