[x = 4y+7 |2x - 6y = 12 What are x and y

Carol wants to make a quilt using a scale of 1.5 inches=2 feet. Her scale drawing is 7.5 inches by 10.5 inches. What is the area

cestrela7 [59]

Answer:

140 ft

Step-by-step explanation:

7 0

3 years ago

Hexagon DEFGHI is translated on the coordinate plane below to create hexagon D'E'F'G'H'I':

dem82 [27]

Hexagon DEFGHI is translated on the coordinate plane below to create hexagon D'E'F'G'H'I'
 the translation of hexagon DEFGHI to hexagon D'E'F'G'H'I' is represents by the rule
 d. (x, y)→(x + 7, y − 7)
I ---> (-8, 4)→(x + 7, y − 7)
I' →(-8 + 7, 4 − 7) = (-1,-3)

5 0

3 years ago

How many terms of the arithmetic sequence {1,22,43,64,85,…} will give a sum of 2332? Show all steps including the formulas used

MA_775_DIABLO [31]

There's a slight problem with your question, but we'll get to that...

Consecutive terms of the sequence are separated by a fixed difference of 21 (22 = 1 + 21, 43 = 22 + 21, 64 = 43 + 21, and so on), so the n-th term of the sequence, a (n), is given recursively by

• a (1) = 1

• a (n) = a (n - 1) + 21 … … … for n > 1

We can find the explicit rule for the sequence by iterative substitution:

a (2) = a (1) + 21

a (3) = a (2) + 21 = (a (1) + 21) + 21 = a (1) + 2×21

a (4) = a (3) + 21 = (a (1) + 2×21) + 21 = a (1) + 3×21

and so on, with the general pattern

a (n) = a (1) + 21 (n - 1) = 21n - 20

Now, we're told that the sum of some number N of terms in this sequence is 2332. In other words, the N-th partial sum of the sequence is

a (1) + a (2) + a (3) + … + a (N - 1) + a (N) = 2332

or more compactly,

$\displaystyle\sum_{n=1}^N a(n) = 2332$

It's important to note that N must be some positive integer.

Replace a (n) by the explicit rule:

$\displaystyle\sum_{n=1}^N (21n-20) = 2332$

Expand the sum on the left as

$\displaystyle 21 \sum_{n=1}^N n-20\sum_{n=1}^N1 = 2332$

and recall the formulas,

$\displaystyle\sum_{k=1}^n1=\underbrace{1+1+\cdots+1}_{n\text{ times}}=n$

$\displaystyle\sum_{k=1}^nk=1+2+3+\cdots+n=\frac{n(n+1)}2$

So the sum of the first N terms of a (n) is such that

21 × N (N + 1)/2 - 20N = 2332

Solve for N :

21 (N ² + N) - 40N = 4664

21 N ² - 19 N - 4664 = 0

Now for the problem I mentioned at the start: this polynomial has no rational roots, and instead

N = (19 ± √392,137)/42 ≈ -14.45 or 15.36

so there is no positive integer N for which the first N terms of the sum add up to 2332.

4 0

3 years ago

Which of the following represents a combination? Select all that apply.

Svetradugi [14.3K]

Answer:

Combinations:

A committee consisting of three members with the same role

Selecting two sandwiches from a menu of 10

Step-by-step explanation:

A combination is a selection of items from a collection, such that the order of selection does not matter.

A permutation is a selection of items from a collection, such that the order of selection matters.

A. The PIN for a bank or credit card - order matters → permutation

B. A committee consisting of three members with the same role - order does not matter → combination

C. A committee consisting of a president, vice president, and secretary - order matters → permutation

D. Final standings in a professional sports league - order matters → permutation

E. Selecting two sandwiches from a menu of 10 - order does not matter → combination

3 0

3 years ago

How many roots does this has? x^2+(2√5x)+2x=-10 find Discriminant

Alexxandr [17]

Given:

The equation is

$x^2+(2\sqrt{5})+2x=-10$

To find:

The number of roots and discriminant of the given equation.

Solution:

We have,

$x^2+(2\sqrt{5})x+2x=-10$

The highest degree of given equation is 2. So, the number of roots is also 2.

It can be written as

$x^2+(2\sqrt{5}+2)x+10=0$

Here, $a=1, b=(2\sqrt{5}+2), c=10$ .

Discriminant of the given equation is

$D=b^2-4ac$

$D=(2\sqrt{5}+2)^2-4(1)(10)$

$D=20+8\sqrt{5}+4-40$

$D=8\sqrt{5}-16$

$D\approx 1.89>0$

Since discriminant is $8\sqrt{5}-16\approx 1.89$ , which is greater than 0, therefore, the given equation has two distinct real roots.

3 0

3 years ago