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tekilochka [14]
3 years ago
10

Solve this system of equations 3x-5y=7 4x+10y=16

Mathematics
1 answer:
seropon [69]3 years ago
4 0
Solve the following system:
{3 x - 5 y = 7 | (equation 1)
{10 y - 4 x = 16 | (equation 2)


Swap equation 1 with equation 2:
{-(4 x) + 10 y = 16 | (equation 1)
{3 x - 5 y = 7 | (equation 2)

Add 3/4 × (equation 1) to equation 2:
{-(4 x) + 10 y = 16 | (equation 1)
{0 x+(5 y)/2 = 19 | (equation 2)


Divide equation 1 by 2:
{-(2 x) + 5 y = 8 | (equation 1)
{0 x+(5 y)/2 = 19 | (equation 2)


Multiply equation 2 by 2:
{-(2 x) + 5 y = 8 | (equation 1)
{0 x+5 y = 38 | (equation 2)

Divide equation 2 by 5:
{-(2 x) + 5 y = 8 | (equation 1)
{0 x+y = 38/5 | (equation 2)

Subtract 5 × (equation 2) from equation 1:
{-(2 x)+0 y = -30 | (equation 1)
{0 x+y = 38/5 | (equation 2)

Divide equation 1 by -2:
{x+0 y = 15 | (equation 1)
{0 x+y = 38/5 | (equation 2)
Collect results:
Answer:  {x = 15
                {y = 38/5 or 7.6 decimal
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The quantity demanded x of a certain brand of DVD player is 3000/week when the unit price p is $485. For each decrease in unit p
ANTONII [103]

Answer:

Demand Equation: q = 15125 - 25p.

Supply Equation: 80p - 24000 = 9q.

Equilibrium Price: $525.

Equilibrium Quantity: 2000 units.

Step-by-step explanation:

To solve this question, first, the demand equation has to be calculated. Let price be on the y-axis and quantity by on the x-axis. It is given that p = $485 when q = 3000 units. This can also be written as (q₁, p₁) = (3000, 485). It is also given that when the price goes down by $20, the quantity increases by 500 units. Therefore, (q₂, p₂) = (3500, 465). Due to the statement "For each decrease in unit price of $20 below $485, the quantity demanded increases by 500 units", the demand function will be linear i.e. a straight line. This is because the word "for each" has been used. Therefore, finding the equation of the demand function:

(p - p₁)/(q - q₁) = (q₂ - q₁)/(p₂ - p₁).

(p - 485)/(q - 3000) = (465 - 485)/(3500 - 3000).

(p - 485)/(q - 3000) = (-20)/(500).

(p - 485)/(q - 3000) = -1/25.

25*(p - 485) = -1*(q - 3000).

25p - 12125 = -q + 3000.

25p + q = 15125.

q = 15125 - 25p. (Demand Equation).

Second, find the supply equation. It is given that the suppliers will not sell the product below or at the price of $300. Therefore, (q₁, p₁) = (0, 300). Also, the suppliers will sell 2000 units if the price is $525. Therefore, (q₂, p₂) = (2000, 525). Since it is mentioned that supply equation is linear, therefore:

(p - p₁)/(q - q₁) = (q₂ - q₁)/(p₂ - p₁).

(p - 300)/(q - 0) = (525 - 300)/(2000 - 0).

(p - 300)/(q) = (225)/(2000).

(p - 300)/(q) = 9/80.

80*(p - 300) = 9*(q).

80p - 24000 = 9q. (Supply Equation).

Equilibrium exists when demand = supply. This means that the demand and the supply equations have to be solved simultaneously. Therefore, put demand equation in supply equation:

80p - 24000 = 9(15125 - 25p).

80p - 24000 = 136125 - 225p.

305p = 160125.

p = $525.

Put p = $525 in demand equation:

q = 15125 - 25p.

q = 15125 - 25(525).

q = 15125 - 13125.

q = 2000 units.

To summarize:

Demand Equation: q = 15125 - 25p!!!

Supply Equation: 80p - 24000 = 9q!!!

Equilibrium Price: $525!!!

Equilibrium Quantity: 2000 units!!!

8 0
3 years ago
There are 4,389 dogwood trees in the state park. The park workers are going to plant 342 more trees. How many trees will there b
Dmitrij [34]

Answer:

4731

Step-by-step explanation:

4,389+342=4,731

6 0
3 years ago
A store manager predicts that 115 hats will be sold if each hat costs $18. The manager predicts that 3 less hats will be sold fo
8_murik_8 [283]

Answer:

The prices at which manager predict that at least 55 hats will be sold would be would be of $38

Step-by-step explanation:

According to the given data we the following:

Number of hats sold at $18=115

The manager predicts at 3 less will sold for every rise in 1 $ for at least 55 hats.

Therefore, reduction in number=115 hats-55 hats=60

So, increase in price=reduction in number/number of hats manager predicts that  will be sold for every $1 increase in price

increase in price=60/3=$20

Therefore, prices at which manager predict that at least 55 hats will be sold would be=$18+$20=$38

The prices at which manager predict that at least 55 hats will be sold would be would be of $38

8 0
3 years ago
I need help lol. Find the lateral surface area of the figure to the nearest tenth.
Mekhanik [1.2K]

Answer:

101.9 sq ft

Step-by-step explanation:

The figure is missing: find it in attachment.

Here we want to find the lateral surface area of the figure, which is the sum of the areas of all faces.

We have in total 5 faces:

- 1 of them is rectangle with sizes (8.5 ft x 3.3 ft), so its area is

A_1=8.5 \cdot 3.3 =28.1 ft^2

- 1 of them is a rectangle with sizes (3.3 ft x 5.1 ft), so its area is

A_2 = 3.3\cdot 5.1 =16.8 ft^2

- 1 of them is a rectangle with sizes (6.8 ft x 3.3 ft), so its area is

A_3 = 6.8\cdot 3.3 =22.4 ft^2

- Finally, we have 2 triangular faces (top and bottom), so their area is

A_T=\frac{1}{2}bh

where

b = 5.1 ft is the base

h = 6.8 ft is the height (because the triangle is a right triangle)

So the area of the triangle is

A_T=\frac{1}{2}(5.1)(6.8)=17.3 ft^2

So the total lateral surface area of the figure is:

A=A_1+A_2+A_3+2A_T=28.1+16.8+22.4+2(17.3)=101.9 ft^2

5 0
3 years ago
In the discussion box, write the next there numbers in each sequence 4,8,12,16__,__,__
frosja888 [35]

Answer:

20,24,28

Step-by-step explanation:

3 0
3 years ago
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