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3 years ago

{2x+7y=2 {y= -2x-1 Am I right?

Mathematics

1 answer:

vampirchik [111]3 years ago

6 0

Okay so we have. 2x + 7y = 2 y = - 2x - 1 Rearranging the second expression we have y + 2x = -1; So 2x + y = -1 2x + 7y = 2 2x + y = -1 Subtracting both eqns we have (2x - 2x) + (7y-y) = 2-(-1). So we have 6y =3; y = 0.5 Substituting into second eqn we have 2x + 0.5 = -1. 2x = -1-0.5=-1.5. Hence x = --0.75. So we have to check for consistency if we would confirm the expression. So Substiting values of x and y into the first eqn we have 2(-0.75) + 7(0.5) = -1.5 + 3.5 =2. And into the second eqn we have 2(-0.75) + 0.5 =-1.5 + 0.5 =-1. So, yes! You are dead right.

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He measured the pool’s dimensions to be 15 feet long by 35 feet wide. The actual dimensions of the pool are 14.5 feet by 34.75 f

mote1985 [20]

Answer:

Percent error = -4.02 (Approx.)

Step-by-step explanation:

Given:

Estimated pool dimension = 15 ft long and 35 ft wide

Actual pool dimension = 14.5 ft long and 34.75 ft wide

Find:

Percent error

Computation:

Area of Estimated pool = 15 x 35

Area of Estimated pool = 525 ft²

Area of Actual pool = 14.5 x 34.75

Area of Actual pool = 508.875 ft²

Percent error = [(Actual - Estimated) / Estimated]100

Percent error = [(508.875 - 525) / 525]100

Percent error = [(-21.125) / 525]100

Percent error = -4.02 (Approx.)

3 0

2 years ago

Using principle of mathematical induction prove that 6^-1 divisble by 5 .

salantis [7]

I suppose the claim is $5 \mid 6^n - 1$ for $n\in\Bbb N$ .

When $n=1$ , we have $6^1 - 1 = 6 - 1 = 5$ , and of course 5 divides 5.

Assume the claim holds for $n=k$ , that $5 \mid 6^k - 1$ . We want to use this to show it holds for $n=k+1$ , that $5 \mid 6^{k+1} - 1$ .

We have

$6^{k+1} - 1 = \left(6^{k+1} - 6\right) + \left(6 - 1) = 6\left(6^k - 1\right) + 5$

Since $5 \mid 6^k - 1$ , we can write $6^k - 1 = 5\ell$ for some integer $\ell$ . Then

$6^{k+1} - 1 = 6\cdot5\ell + 5 = 5(6\ell + 1)$

which is clearly divisible by 5. QED

5 0

1 year ago

If half of the pie below is eaten what fraction remains

Maksim231197 [3]

Is there a picture we can see if it’s a whole pie than 1/2

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3 years ago

What is the positive solution to the equation 0 = 3x2-31 ?

Bas_tet [7]

Answer:

4.47

Step-by-step explanation:

3x²+31=91

3x²=91-31

3x²=60

x²=60÷3

x²=20

x=√20

x=4.47

6 0

2 years ago

Tanya is training a turtle for a race. For every 1/2 of an hour that the turtle is crawling, he can travel 3/20 of a mile. At wh

vazorg [7]

Answer:

$\frac{6}{20} \ mile\ per\ hour$

Step-by-step explanation:

Given:

For every 1/2 of an hour that the turtle is crawling, he can travel 3/20 of a mile

Question asked:

At what unit rate is the turtle crawling?

Solution:

As here time taken is given and the distance traveled is also given and hence we will apply speed and distance formula to find rate of crawling of turtle.

Time taken by turtle = $\frac{1}{2} \ hour$

Distance which can be traveled by turtle = $\frac{3}{20} \ miles$

$Speed =\frac{Distance}{Time}$

$=\frac{3}{20} \div\frac{1}{2} \\\\ =\frac{3}{20} \times\frac{2}{1} \\ \\ =\frac{6}{20}$

Therefore, the rate at which the turtle is crawling is $\frac{6}{20} \ mile\ per\ hour$

4 0

2 years ago