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77julia77 [94]
3 years ago
10

Isaac downloaded 7 ringtones. Each polyphonic ringtone costs $3.25, and each standard ringtone costs $1.50. If he spends a total

of $21 on ringtones, find the number of polyphonic and standard ringtones he downloaded.
Mathematics
2 answers:
anzhelika [568]3 years ago
6 0

Answer:

6\ polyphonic\ ringtones  and 1\ standard\ ringtone

Step-by-step explanation:

Let

x -----> the number of polyphonic ringtones

y ----> the number of standard ringtones

we know that

x+y=7

x=7-y -----> equation A

3.25x+1.50y=21 -----> equation B

Solve the system of equations by substitution

Substitute equation A in equation B and solve for y

3.25(7-y)+1.50y=21

22.75-3.25y+1.50y=21

3.25y-1.50y=22.75-21

1.75y=1.75

y=1\ standard\ ringtones

Find the value of x

x=7-1=6\ polyphonic\ ringtones

Vlad1618 [11]3 years ago
4 0

Answer:

6 polyphonic, 1 standard

Step-by-step explanation:

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<h3>Answer: Yes it is linear.</h3>

Explanation:

The given equation is the same as y = 0x - 7. It matches the form y = mx+b which is slope intercept form of a linear equation.

The slope m = 0 always applies to horizontal lines. All points on this line have a y coordinate of -7.

7 0
2 years ago
Write the equation of the line with a slope of 0 and containing the point (- 6, 5).
defon
Y=mx+b
5=0(-6)+b
b=5
So equation
y=0x+5

Or

y=5
4 0
3 years ago
Carlos deposited $7,924 into a savings account 30 years ago. The account has an interest rate of 4.6% and the balance is current
exis [7]

Answer:

n = 1, this means the interest compounds ANNUALLY.

Step-by-step explanation:

Carlos deposited $7,924 into a savings account 30 years ago. The account has an interest rate of 4.6% and the balance is currently $30,541.83. How often does the interest compound?

Compound Interest Formula

: A = P(1 + r/n)^nt

A = Amount after time t

P = Principal (Initial Amount Invested)

r = Interest rate

n = Number of times the interest is compounded

t = time in years

A = $30,541.83

r = 4.6% = 0.046

t = 30

P = $7,924

Hence,

$30,541.83 = $7924(1 + 0.046/n)^30n

Divide both sides by 7924

$30,541.93/$7924 = (1 + 0.046/n)^30n

$30,541.93/$7924 = (n + 0.046/n)^30n

3.8543576477 = (n + 0.046/n)^30n

We take the logarithm of both sides

log 3.8543576477 = log (n + 0.046/n)^30n

Solving for n,

n = 1

Therefore, from the calculation above, since n = 1, this means the interest compounds ANNUALLY.

6 0
2 years ago
8 x - 4 (5 - x) = -44
Sphinxa [80]

8 x - 4 (5 - x) = -44

mutiply the bracket by -4

(-4)(5) = -20

(-4)(-x)= 4x

8x-20+4x= -44

8x+4x-20= -44 ( combine like terms )

12x-20= -44

move -20 to the other side

sign changes from -20 to +20

12x-20+20= -44+20

12x= -44+20

12x= -24

divide both sides by 12

12x/12= -24/12

Answer: x= -2

3 0
3 years ago
I need help with #11 MULTIPLE CHOICE
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Answer:

d

Step-by-step explanation:

8 0
3 years ago
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