math plz help
posted by electroShark797 .
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.
x | y
1 | 1
2 | 1 + 2
3 | 1 + 2 +4
4 | 1 + 2 + 4 + 8
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?
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(10-c)
total cost = 12c + 20(10-c)
= 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?