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Pepsi [2]
3 years ago
5

When 21 is subtracted from the square of a number, the result is 4 times the number. Find the positive solution.

Mathematics
1 answer:
wel3 years ago
7 0

Let x = your number.

x^2 - 21 = 4x. Subtract 4x from both sides.

x^2 - 4x - 21 = 0. Factor.

(x - 7) (x + 3) = 0. Set each term to 0.

x + 3 = 0. Subtract 3 from both sides.

x = -3. This is the negative solution.

Set the other term equal to zero.

x - 7 = 0. Add 7 to each side.

x = 7. This is the positive solution.

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HELP PLEASE
Fantom [35]

Answer:

Option C

Step-by-step explanation:

You forgot to attach the expression that models the cost of the camping trip during the three days. However, by analyzing the units, the answer can be reached.

The total cost has to be in units of $.

There are two types of costs in the problem:

Those that depend on the number of days ($/day )

Those that depend on the number of students and the number of days ($/(student * day))

If there are 3 days of camping and b students, then you have to multiply the costs that depend on the days by the number of days (3), and the costs that depend on the number of students you have to multiply them by 'b'

So, if the costs that must be multiplied by 'b' are only those that depend on the number of students, the coefficient of b must be:

3 days (Cost of training + Cost of food Miscellaneous expenses :).

Therefore the correct answer is option C:

C. It is the total cost of 3 days per student of Mr. Brown, with training, food and miscellaneous expenses.

The expression that represents the total expense should have a formula similar to this:

y = (3 days) *([\frac{20.dollars}{(day * student)} + \frac{30.dollars}{(student * day)} + \frac{50.dollars}{(student * day)}] b + \frac{200}{day}) + 1050.dollars

y = 3 ($ 100b + $ 200) + $ 1050

3 0
3 years ago
Read 2 more answers
Brielle and Joshua are running a half marathon race, which is 13.1 miles long. It
Hitman42 [59]

Answer:Brielle will run the half marathon race faster.Brielle will take 1 hour 44 minutes and 48 seconds, Joshua will take 2 hours 37 minutes and 12 seconds

Step-by-step explanation:

10 / 1.25 = 8

8 minutes a mile

18 / 1.5 = 12

12 minutes a mile

Brielle will run the half marathon race faster.

8 x 13.1 =104.8

12 x 13.1=157.2

104.8 - 60=

44.8

60 seconds x .8= 48

Brielle will take 1 hour 44 minutes and 48 seconds

157.2 - 120 = 37.2

60 seconds x .2 = 12

Joshua will take 2 hours 37 minutes and 12 seconds

8 0
4 years ago
What are the 5 Key components for graphing the Parabola of a Quadratic Function?
ivolga24 [154]

Answer:

Axis of symmetry

y-intercept

x-intercepts

Vertex

(I forgot the last one)

Step-by-step explanation:

3 0
3 years ago
Find the surface area of the cylinder in terms of pi. 9cm and 19cm
Natali [406]

Answer:

Surface area of cylinder= 211.5π

Step-by-step explanation:

Given,

Height of cylinder = 19cm

Diameter of cylinder = 9cm

i.e Radius of cylinder = diameter/2 = 9/2 = 4.5cm

Surface area of cylinder = 2πrh + 2πr²

Plug corresponding values of r and h in surface are formula.

Surface area of cylinder = 2πrh + 2πr² = 2π*4.5*19 + 2π*4.5²

Surface area of cylinder = 171π+40.5π = 211.5π

Hence we get surface area of cylinder= 211.5π


3 0
3 years ago
Leo is going to solve the equation below. Which of the following statements is true?
mihalych1998 [28]
The answer is A.

Reasoning:
Choice B says to subtract 1/5. However since 1/5 has a variable next to it, it would need to be divided not subtracted
5 0
3 years ago
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