3) a number divided by three is nine more than the number.

Number is x =  -13.5

Step-by-step explanation:

Let the number is x

Given condition:

number divided by three is nine more than the number.

This can be written as:

x/3 = 9 + x

Taking x sides at left of equal will make the signs opposite

x/3 - x = 9

Taking denominators of both terms same (3)

x/3 - x* 3/3 = 9

(x- 3x)/ 3 = 9

-2x/3 =9

Multiplying both sides by -3/2

x = 9*(-3/2)

x = -27/2

x= -13.5

Proof:

Given condition is:

x/3 = 9 + x

Putting value of x

-13.5/3 = 9 + (-13.5)

-4.5 = -4.5

I hope it will help you!

first, we define the variables:

x: number of years after 1950

f (x): amount of vinyl sold.

then, with the variables defined, we have:

68594 vinyl records were sold in 1958 > f (8) = 68594

91299 vinyl records were sold in 1961 > f (11) = 91299

38720 vinyl records were sold in 1952 > f (2) = 38720

161743 vinyl records were sold in 1967 > f (17) = 161743

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step-by-step explanation: