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3 years ago

I'm completely lost

Mathematics

1 answer:

Vladimir [108]3 years ago

4 0

Let x be the number of racing bikes, and let y be the number of mountain bikes.
1) 140x + 110y = 26150
2) 180x + 120y = 31800
Solve for one of the variables and plug that in to the other equation:
From equation 1: 140x = 26150 - 110y
x = (26150-110y)/140
Plug this into equation 2:
180((26150-110y)/140) = 31800
Solve for y, and find that y = 85 (the number of mountain bikes).
Plug that y into either equation to find x:
140x + 110(85) = 26150
x = 120 (the number of racing bikes).
So the answer is: 120 racing bikes and 85 mountain bikes.

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Dvinal [7]

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3 years ago

Read 2 more answers

The system of equations

cupoosta [38]

Answer:

z = -12

Step-by-step explanation:

The given system of equations is:

xy/(x + y) = 1 ...........................(1)

xz/(x + z) = 2...........................(2)

yz/(y + z) = 3...........................(3)

From (1): x + y = xy

=> y = xy - x

y = x(y - 1)

x = y/(y - 1).......................................(4)

From (2): 2(x + z) = xz

=> 2x + 2z = xz

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From (3): 3(y + z) = yz

=> 3y + 3z = yz

3y = yz - 3z

3y = z(y - 3)

z = 3y/(y - 3)....................................(6)

Comparing (5) and (6)

2x/(x - 2) = 3y/(y - 3)

2x(y - 3) = 3y(x - 2)

2xy - 6x = 3xy - 6y

6(y - x) = xy .................................(7)

But from (1): xy = x + y

Using this in (7), we have

6(y - x) = x + y

6y - y - 6x - x = 0

5y - 7x = 0

5y = 7x

x = 5y/7................................................(8)

Using this in (4)

5y/7 = y/(y - 1)

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(y - 1) = 7/5

y = 1 + 7/5

y = 12/5..........................................(9)

Using this in (8)

x = 5(12/5)/7 = 12/7 .......................(10)

Using (10) in (5)

z = 2x/(x - 2)

z = 2(12/7) ÷ (12/7 - 2)

= 24/7 ÷ -2/7

= 24/7 × (-7/2)

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z = -12.

4 0

4 years ago

Math help pls, thank you :3

timurjin [86]

Answer:

- question 2 answer is C. (-1,7) and (6,28)

- question 3 answer is A. it is possible for a system of equations composed of linear function and a quadratic function to have 3 solutions.

- question 4 answer is (1,6)

P.s. if any question is wrong then I'm sorry. :(

Step-by-step explanation:

question 4

y=2x^2-5x+9

y= 2x^2+5x-1

y= 2x^2-5x+9=2x^2+5x-1

x=1

y= 2×1^2+5×1-1

y=6

7 0

4 years ago

13x + 15=17x-13 solve for the solution

Archy [21]

Answer: x=7

Step-by-step explanation:

Step 1: Subtract 17x from both sides.

13x+15−17x=17x−13−17x

−4x+15=−13

Step 2: Subtract 15 from both sides.

−4x+15−15=−13−15

−4x=−28

Step 3: Divide both sides by -4.

−4x/−4 =−28/−4

x=7

6 0

3 years ago

Find the area of the triangle formed by the origin and the points of intersection of parabolas y=− 1/3 (x−1)^2+8 and y=x^2−2x−3.

Kobotan [32]

Answer:

The area of the triangle formed by origin, and the points (4,5) and (-2,5) will be 15 sq. units.

Step-by-step explanation:

The two parabolas are $y = - \frac{1}{3}(x - 1)^{2} + 8$ and y = x² - 2x - 3.

Now, solving those two equations we will get the points of intersection.

So, $- \frac{1}{3}(x - 1)^{2} + 8 = x^{2} - 2x - 3$

⇒ - (x - 1)² + 24 = 3x² - 6x - 9

⇒ -x² + 2x - 1 + 24 = 3x² - 6x - 9

⇒ 4x² - 8x - 32 = 0

⇒ x² - 2x - 8 = 0

⇒ x² - 4x + 2x - 8 = 0

⇒ (x - 4)(x + 2) = 0

So, x = 4 or - 2.

Now, for x = 4 , y = 4² - 2(4) - 3 = 5 and the point of intersection is (4,5).

Or, for x = - 2, y = (- 2)² - 2(- 2) - 3 = 5 and the point of intersection is (-2,5).

Now, points (4,5) and (-2,5) make a straight line parallel to the x-axis at a perpendicular distance of 5 units from origin and its length is (4 - (- 2)) = 6 units.

So, the area of the triangle formed by origin, and the points (4,5) and (-2,5) will be = 0.5 × 5 × 6 = 15 sq. units. (Answer)

8 0

3 years ago