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NNADVOKAT [17]
3 years ago
15

Solve the system of equations x+y=-1 and 5x-7y=79 by combining the equations.

Mathematics
1 answer:
Leya [2.2K]3 years ago
6 0

9514 1404 393

Answer:

  (x, y) = (-6, -7)

Step-by-step explanation:

Multiply the first equation by 7 and add that to the second.

  7(x +y) +(5x -7y) = 7(-1) +(79)

  12x = 72

  x = 6

  y = -1 -x = -1 -6 = -7

The solution is (x, y) = (6, -7).

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A runner is 6/8 mile from the finish line. If she can travel 3/8 mile per minute, how long will it take her to finish the race?
Klio2033 [76]

Answer:

it will take her 40 seconds to finish the race.

3/8 per minute, would make it 1/8 every 20 seconds. since she only has 2/8 of a mile left to go, 20 seconds +20 seconds = 40 seconds

(if you needed how long it takes her to run the whole race, it's 2 minutes 40 seconds, which would make her the fastest mile runner in the world)

Step-by-step explanation:

I hope this helps :)

6 0
3 years ago
Explain how you use estimation to check the reasonableness of a solution to a practical problem.
Oxana [17]

Answer:

Well, one way to use reasonableness is to estimate the answer to see if your answer is an outrageous answer or not. So, looking at your problem, you see that you are multiplying a two hundred something number by 4 and then subtracting 10 from it.

Step-by-step explanation:

3 0
3 years ago
(a) Use the definition to find an expression for the area under the curve y = x3 from 0 to 1 as a limit. lim n→∞ n i = 1 Correct
Luba_88 [7]

Splitting up the interval of integration into n subintervals gives the partition

\left[0,\dfrac1n\right],\left[\dfrac1n,\dfrac2n\right],\ldots,\left[\dfrac{n-1}n,1\right]

Each subinterval has length \dfrac{1-0}n=\dfrac1n. The right endpoints of each subinterval follow the sequence

r_i=\dfrac in

with i=1,2,3,\ldots,n. Then the left-endpoint Riemann sum that approximates the definite integral is

\displaystyle\sum_{i=1}^n\frac{{r_i}^3}n

and taking the limit as n\to\infty gives the area exactly. We have

\displaystyle\lim_{n\to\infty}\frac1n\sum_{i=1}^n\left(\frac in\right)^3=\lim_{n\to\infty}\frac{n^2(n+1)^2}{4n^3}=\boxed{\frac14}

6 0
3 years ago
Determine whether each quadrilateral is a parallelogram. Justify your answer.
Lina20 [59]

Answer:

4. Parallelogram

5. Parallelogram

6. Parallelogram

Step-by-step explanation:

  • 4. This is a parallelogram because the longer sides are parallel to each other and the shorter sides are also parallel to each other. Hence, this is a parallelogram.
  • 5. This is a parallelogram because it's angles are the same to the opposite angles. Hence, this is a parallelogram.
  • 6. This is a parallelogram because the longer sides are parallel to each other and the shorter sides are also parallel to each other. Hence, this is a parallelogram.

Hoped this helped.

4 0
2 years ago
From a pile of 100 pennies(P), 100 nickels(N), and 100 dimes(D), select 21 coins which have a total value of exactly $1.00. In y
Murrr4er [49]
So, you need 10 penny, 4 nickles and 7 dimes
Lets, check it.
According to the question,
total coins = 21
7 + 4 + 10 = 21
21 = 21.........................................true
Now,
their value should equal $1.00 = 100 cents
Penny = 1 cent
nickle = 5 cent
dime = 10 cent,
So,
(10 *1) + (4 * 5) + (7 * 10) = 100
10 + 20 + 70 = 100
100 = 100......................................true

 
So, you need 10 penny, 4 nickle, and 7 dimes
4 0
3 years ago
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