Which choice correctly shows the solution(s) of the equation x2 = 400?

Two planes leave an airport at noon. If the eastbound plane flies at 660 mph and the westbound plane flies at 600 mph, at what t

Eddi Din [679]

I'm guessing that they took of in the same airport.

Each hour they will separate by 1260 miles or 21 miles each minute

2,000/21 = 95.23 minutes which is 1 hour and 35 minutes

Hope this helps :)

6 0

3 years ago

The total cost (in dollars) for a company to manufacture and sell x items per week is C = 40 x + 640 , whereas the revenue broug

ikadub [295]

Answer:

The company must sell 60 or 70 items to obtain a weekly profit of 200.

Step-by-step explanation:

The profit is the difference between the revenue and the cost of a given task, therefore:

$\text{profit} = R - C\\\text{profit} = 66*x - 0.2*x^2 - (40*x + 640)\\\text{profit} = 66*x - 0.2*x^2 - 40*x - 640\\\text{profit} = - 0.2*x^2 + 26*x - 640$

To have a profit of 200, we need to sell:

$-0.2*x^2 + 26*x - 640 = 200\\-0.2*x^2 + 26*x -840 = 0\text{ } *\frac{-1}{0.2}\\x^2 -130 + -4200 = 0\\x_{1,2} = \frac{-(-130) \pm \sqrt{(-130)^2 - 4*1*(-4200)}}{2*1}\\x_{1,2} = \frac{130 \pm \sqrt{16900 + 16800}}{2}\\x_{1,2} = \frac{130 \pm \sqrt{100}}{2}\\x_{1,2} = \frac{130 \pm 10}{2}\\x_{1} = \frac{130 + 10}{2} = \frac{140}{2} = 70\\ x_{2} = \frac{130 - 10}{2} = \frac{120}{2} = 60$

The company must sell 60 or 70 items to obtain a weekly profit of 200.

3 0

3 years ago

Classify each pair of angles listed below as adjacent or vertical.

Roman55 [17]

Given:

Intersecting lines DA and CE.

To find:

Each pair of adjacent angles and vertical angles.

Solution:

Adjacent angles are in the same straight line.

<u>Pair of adjacent angles:</u>

(1) ∠EBD and ∠DBC

(2) ∠DBC and ∠CBA

(3) ∠CBA and ∠ABE

(4) ∠ABE and ∠EBD

Vertical angles are opposite angles in the same vertex.

<u>Pair of vertical angles:</u>

(1) ∠EBD and ∠CBA

(2) ∠DBC and ∠EBA

5 0

3 years ago

To subtract a fraction or a mixed number from a whole number, you’ll first need to convert the whole number to which of the foll

ladessa [460]

IMproper fraction is what you need to covert it 2 cuz u multiply then add and u'll get it

8 0

3 years ago

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A 31-inch piece of steel is cut into three pieces so that the second piece is twice as long as the first piece, and the third

Nostrana [21]

Answer:

The length of the first piece is 4 inches, that of the second is 8 inches and the third 19 inches.

Step-by-step explanation:

Total length of the steel = 31 inches

Let the length of the first piece = x

let the length of the second piece = y

Let the length of the third piece = z

So,

y = 2x

z = 4x + 3

x + 2x + 4x +3 = total length of the steel = 31

7x + 3 + 31

7x = 31 - 3

7x = 28

x= 4 inches

Thus; y = 2x = 2 × 4 = 8 inches

z = 4x +3 = 4×4 +3 =19 inches

∴The length of the first piece is 4 inches, that of the second is 8 inches and the third 19 inches.

6 0

3 years ago

Read 2 more answers