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shtirl [24]
3 years ago
12

Phillip bought 12 used CDs and DVDs. CDs cost $2 each, and DVDs cost $3 each. He spent $31, not including tax. How many DVDs did

Phillip buy?
Mathematics
2 answers:
Volgvan3 years ago
7 0

He got 7 dvds, answer is c on flvs

Ghella [55]3 years ago
6 0
So he bought 12 CDs and DVDs (in total), CDs + DVDs = 12

Each cd is 2 and each cd is 3

Total spent = 31 (2*x + 3*y)

I call x cds and y dvds

x+y = 12

2x+3y = 31

Solve for y

Move x to the right with changed sign

y = 12-x (DVDs, you can also write x = 12-y)

And substitute 12-y in the equation

2x + 3(12-x) = 31

2x + 36 - 3x = 31

2x - 3x = 31 - 36

-x = -5

x = 5 (CDs)

To find DVDs let's rewrite y = 12-x

y = 12-5 = 7 (DVDs)
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How is the quotient 80,000÷2000 different from the quotient 80,000÷200 or 80,000÷20
Olegator [25]
 2,000, 200 and 20 are similar except for the number of zeros.
You can remove a zero from each to equal the number of zeros in the divisor.  So 80,000 ÷ 2,000 is equivalent to 80 ÷ 2 = 40  you just remove the 3 zeros
80,000 ÷ 200 is equivalent to 800 ÷ 2 = 400 you just keep removing 0s like for instance this time it was 2 lastly 80,000 ÷ 20 only allows us to remove 1 zero 8,000 ÷ 2 = 4,000. The smaller the divisor the greater the quotient when dividing the same number like for instance in this example 80,000
3 0
3 years ago
2x + y = 12
Arlecino [84]

Answer:

Whats the question?

Step-by-step explanation:

8 0
3 years ago
Read 2 more answers
Determine the values of a for which the following system of linear equations has no solutions, a unique solution, or infinitely
navik [9.2K]

Answer:

Never

Never

Never

Step-by-step explanation:

The equations given are

2x1−6x2−4x3 = 6 ....... (1)

−x1+ax2+4x3 = −1 ........(2)

2x1−5x2−2x3 = 9 ..........(3)

the values of a for which the system of linear equations has no solutions

Let first add equation 1 and 2. Also equation 2 and 3. This will result to

X1 + (a X2 - 6X2) - 0 = 5

And

X1 + (aX2-5X2) + 2X3 = 8

Since X2 and X3 can't be cancelled out, we conclude that the value of a is never.

a unique solution,

Let first add equation 1 and 2. Also equation 2 and 3. This will result to

X1 + (a X2 - 6X2) - 0 = 5

And

X1 + (aX2-5X2) + 2X3 = 8

The value of a = never

infinitely many solutions. 

Divide equation 1 by 2 we will get

X1 - 3X2 - 2X3 =3

Add the above equation with equation 3. This will result to

3X1 - 8X2 - 4X3 = 12

Everything ought to be the same. Since they're not.

Value of a = never.

4 0
3 years ago
What is thirty two percent of fifty six
mojhsa [17]

Answer: 17.92

Step-by-step explanation:

32% of 56  

Change to fraction

32 /100 x 56

Change to decimal

0.32 x 56

= 17.92

5 0
3 years ago
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