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# Need some help ASAP on knowledge practice problems

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Can you solve these???

1.

A package of paper towels contains 3 rolls. Each package of paper towels costs \$2.79.​

A function, f(x), is written to represent the cost of purchasing x packages of paper towels.

What is the practical domain for the function f(x)?

all real numbers

all positive integers

all whole numbers

all whole numbers that are multiples of 3

2.

A spinner is divided into four equal sections that are numbered 2, 4, 7, and 9. The spinner is spun twice.

How many outcomes have a product less than 30 and contain at least one odd number?

5

6

8

10

3.

Solve the system of equations.

y=x+6

y=x^2+8x+16

____,_____ or_______,______

Thank you so much!!! Really struggling but I have to get these done soon.

May 27, 2019

#1
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1.  all whole numbers

2.

Below are all possible outcomes:

2, 2       4, 2       7, 2       9, 2

2, 4       4, 4       7, 4       9, 4

2, 7       4, 7       7, 7       9, 7

2, 9       4, 9       7, 9       9, 9

The ones colored blue are the ones which have a product less than 30 and contain at least one odd number.

There  are  6  of them.

3.

y  =  x + 6

y  =  x2 + 8x + 16                Substitute  x + 6  in for  y  in this equation.

x + 6  =  x2 + 8x + 16

Subtract  x  and subtract  6  from both sides.

0  =  x2 + 7x + 10

Factor the right side.

0  =  (x + 2)(x + 5)

Set each factor equal to zero and solve for  x .

x + 2 = 0     or     x + 5 = 0

x  =  -2       or       x  =  -5

When  x  =  -2 ,     y  =  x + 6  =  -2 + 6  =  4       So  (-2, 4)  is a solution.

When  x  =  -5 ,     y  =  x + 6  =  -5 + 6  =  1       So  (-5, 1)  is a solution.

May 27, 2019

#1
+3

1.  all whole numbers

2.

Below are all possible outcomes:

2, 2       4, 2       7, 2       9, 2

2, 4       4, 4       7, 4       9, 4

2, 7       4, 7       7, 7       9, 7

2, 9       4, 9       7, 9       9, 9

The ones colored blue are the ones which have a product less than 30 and contain at least one odd number.

There  are  6  of them.

3.

y  =  x + 6

y  =  x2 + 8x + 16                Substitute  x + 6  in for  y  in this equation.

x + 6  =  x2 + 8x + 16

Subtract  x  and subtract  6  from both sides.

0  =  x2 + 7x + 10

Factor the right side.

0  =  (x + 2)(x + 5)

Set each factor equal to zero and solve for  x .

x + 2 = 0     or     x + 5 = 0

x  =  -2       or       x  =  -5

When  x  =  -2 ,     y  =  x + 6  =  -2 + 6  =  4       So  (-2, 4)  is a solution.

When  x  =  -5 ,     y  =  x + 6  =  -5 + 6  =  1       So  (-5, 1)  is a solution.

hectictar May 27, 2019
#2
+2

Thank you soo much for your help and explanations!!!!

PhoenixForever  May 27, 2019