math plz help
posted by electroShark797 on .
Task 2:
Use the table to complete each part.
a. Copy the table. Extend the table by writing expressions for y when x = 5, 6, and 7.
b. Simplify each expression for y in the table from part (a). What pattern do you notice in the simplified expressions?
c. Write an equation that relates x and y. Us your equation to find the value of y when x = 15.
The Table:
x  y
1  1
2  1 + 2
3  1 + 2 +4
4  1 + 2 + 4 + 8

plz help!

let's get the actual answers for the y values
x  y
1  1 = 1
2  1 + 2 = 3
3  1 + 2 +4 = 7
4  1 + 2 + 4 + 8 = 15
5  1+2+4+8+16 = 32
6  1+2+4+8+16+32 = 63
Did you notice that all the sums are one less than a power of 2
e.g for x = 3, the sum = 7 = 2^3  1
for x = 6 , the sum = 63 = 2^6  1
so when x = 15, the sum should be 2^15  1 = 32767 
Okay thanks can you help with this one?
Task 3:
Solve. Show all your work and explain your steps.
You are buying gifts for 10 people. You decide to buy each person either a CD or a DVD. A CD costs $12 and a DVD cost $20.
a. Let c = the number of CDs you decide to buy. What is an expression in terms of c for the number of DVDs you buy?
b. What is an expression in terms of c for the cost of the CDs? For the cost of the DVDs?
c. Write and simplify an expression in terms of c for the total cost of all the gifts you buy. 
Let c = the number of CDs you decide to buy
Then the number of DVDs is 10  c
cost of CD = 12c
cost of DVD = 20(10c)
total cost = 12c + 20(10c)
= 12c + 200  20c
= 200  8c 
thank you ssssoooooo much !

The property used is Distributive correct? Would we say it has commutative property of addition as well or just Distributive?
thanks