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2 years ago

Please solve 21=5n-2(n-3)

Mathematics

2 answers:

Stella [2.4K]2 years ago

8 0

21 = 5n-2(n-3)

21 = 5n-2n+6

21-6 = 3n

n=15/3

n=5

grigory [225]2 years ago

3 0

5=n because you multiply -2 times n then -3 then you add -2n with 5n then subtract 6 from both sides and finally divide by 3

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Physics students were modeling the height of a ball once it was dropped from the top of a 10 foot ladder. The

julsineya [31]

Answer:

Interval notation: [0, 2.236]

Set Builder notation: $\{t\ |\ 0\le t\le 2.236\}$

Step-by-step explanation:

Given that:

Equation of height of the ball dropped from a height of 10 foot, as:

$h(t) = 10 - 2t^2$

Where $t$ is the time since the ball was dropped.

To find:

The domain of the function in Interval and set builder notation.

Solution:

Domain of a function is defined as the set of valid input values that can be given to the function for which the function is defined.

Here, input is time.

We can not have negative values for time.

Therefore, starting value for time will be 0 seconds.

And the value of height can not be lesser than that of 0 ft.

$0= 10 - 2t^2\\\Rightarrow 2t^2=10\\\Rightarrow t^2=5\\\Rightarrow t =2.236\ seconds$

Maximum value for time can be 2.236 seconds.

Therefore the domain is:

Interval notation: [0, 2.236]

Set Builder notation: $\{t\ |\ 0\le t\le 2.236\}$

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2 years ago

The sum of the areas of two circles is 80 pi

katovenus [111]

The area of a circle is A = πr^2. We let A1 And A2 the areas of the circles and r1 and r2 the radius of each, respectivley.

A1 + A2 = 80π
Substitute the formula for the area,
π(r1)^2 + π (r2)^2 = 80π

From the statement, we know that r2=2(r1).

π(r1)^2 + π (2 x r1)^2 = 80π
We can cancel π, we will have

5 x (r1)^2 = 80
Thus,

r1 = 4 and r2 = 8

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2 years ago

Write an equation for the table 2 5 5.6 14 7 17.5 8 20

vova2212 [387]

The equation for the table is y = 2.5 x

Step-by-step explanation:

The table is:

x → 2 : 5.6 : 7 : 8
y → 5 : 14 : 17.5 : 20

Lets check if the table represents the linear relation by find the ratio between the change of each two consecutive y-coordinates and the change of their corresponding x-coordinates

∵ $\frac{14-5}{5.6-2}=\frac{9}{3.6}=2.5$

∵ $\frac{17.5-14}{7-5.6}=\frac{3.5}{1.4}=2.5$

∵ $\frac{20-17.5}{8-7}=\frac{2.5}{1}=2.5$

∴ The rate of change between each two points is constant

∴ The table represent a linear equation

The form of linear equation is y = m x + b, where m is the rate of change and b is value y when x = 0

∵ m = 2.5

- Substitute it in the form of the equation

∴ y = 2.5 x + b

- To find b substitute x and y by the coordinates of any point

in the table above

∵ x = 2 and y = 5

∴ 5 = 2.5(2) + b

∴ 5 = 5 + b

- Subtract 5 from both sides

∴ 0 = b

∴ y = 2.5 x

The equation for the table is y = 2.5 x

Learn more:

You can learn more about the linear equations in brainly.com/question/4326955

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