If 7 times the 7th term of an AP is equal to 11 times its 11th term, then its 18th term will be

7

18

 

11

0​

Answer:

11 terms.

Step-by-step explanation:

We are given the arithmetic sequence:

17, 13, 9, ...

And we want to find the number of terms required such that the sum is -33.

Recall that the sum of an arithmetic series is given by:

[tex]\displaystyle S = \frac{k}{2}\left( a + x_k\right)[/tex]

Where k is the number of terms, a is the first term, and x_k is the last term.

The desired sum is -33. The first term is 17 as well. Thus:

[tex]\displaystyle (-33) = \frac{k}{2} \left( (17) +x_k\right)[/tex]

Simplify:

[tex]-66 = k(17 + x_k)[/tex]

We can write a direct formula to find the last term x_k. The direct formula of an arithmetic sequence has the form:

[tex]x_ n = a + d(n-1)[/tex]

Where a is the initial term and d is the common difference.

The initial term is 17 and the common difference is -4. Hence:

[tex]\displaystyle x_n = 17 - 4(n-1)[/tex]

Then the last term is given by:

[tex]x_k = 17 - 4(k-1)[/tex]

Substitute:

[tex]\displaystyle -66 = k\left( 17 + \left( 17 - 4(k-1)\right)\right)[/tex]

Solve for k:

[tex]\displaystyle \begin{aligned} -66 &= k(17 + (17 - 4k + 4)) \\ -66 &= k(38 -4k) \\ -66 &= -4k^2 + 38k \\ 4k^2 -38k -66 &= 0 \\ 2k^2 - 19k -33 &= 0 \\ (k-11)(2k+3) &= 0 \\ k-11&= 0 \text{ or } 2k+3 = 0 \\ \\ k &= 11 \text{ or } k = -\frac{3}{2}\end{aligned}[/tex]

Since we cannot have a negative amount of terms, we can ignore the second solution.

Therefore, the given sequence must have 11 terms such that it sums to -33.

Answer:

Here is 2 methods

Step-by-step explanation:

1) we use excel to find n=11 for lasy students

2) mathematical method

[tex]u_1=17\\u_2=13=17+(2-1)*(-4)\\u_3=9=17+(3-1)*(-4)\\\\\\\boxed{u_n=17+(n-1)*(-4)}\\\\\\\displaystyle s_n=\sum_{i=1}^nu_i\\=\sum_{i=1}^n(17+(i-1)*(-4))\\\\\\=(\sum_{i=1}^n 17) + (-4)*\sum_{i=1}^n (i) +4*\sum_{i=1}^n (1)\\\\\\=17*n+4*n-4*\frac{n*(n+1)}{2} \\\\\\=21n-2n^2-2n\\\\\\=-2n^2+19n\\\\=-33\\\\\\\Longrightarrow\ 2n^2-19n-33=0[/tex]

[tex]\Delta=19^2+4*2*33=625=25^2\\\\n=\dfrac{19-25}{4} =-1.5\ (excluded)\ or\ n=\dfrac{19+25}{4}=11\\\\[/tex]

Answer:

emily fills 3 racks

3 basketballs are Left!

Step-by-step explanation:

15/4 = 3.3

Answer:

Step-by-step explanation:

The diagonal of this rectangular box serves as the hypotenuse of the 2 right triangles that exist within this rectangle. The length is one leg, the hypotenuse is...well, the hypotenuse, so we need to use Pythagorean's Theorem to find the missing leg.

[tex]10^2=8^2+x^2[/tex] and

[tex]100-64=x^2[/tex] and

[tex]x^2=36[/tex] so

x = 6. The width is 6.

Answer:

(2,1)

Step-by-step explanation:

2x - 2y = 2

5x + 2y = 12

again just add them in this case

7x = 14

x = 2

4 - 2y = 2

-2y = -2

y = 1

Answer:

vertical

Step-by-step explanation:

The line x = -5 includes all points where the value of x is -5, regardless of the value of y. This can be graphed as a vertical line going through (-5, 0), as the line represents the only place where x is the value -5.

- X + 3Y = 2  (*)

⇔X = 2 - 3Y  (1)

- Y = 2X + 3   (2)

(1),(2)⇒ Y = 2(2 - 3Y) +3

       ⇔ Y = 4 - 6Y + 3

       ⇔ Y = 1  (**)

(*),(**)⇒ X + 3×1 =2

       ⇔ X = -1

Answer:

Divide the number you want to find the percentage for by the total amount of items in that group. Then, multiply that value by 100.

Step-by-step explanation:

Ex. There are 3 boys in a group of 4. What percentage of the group are boys?

[tex]\frac{3}{4} =0.75[/tex]

[tex]0.75*100=75[/tex]

75% of the group are boys

Answer:

Ans no. 1 = 14/15

Ans no. 2= 1/192

Answer:

Its AA similaroty theorem

Answer:

Step-by-step explanation:

[tex]\sqrt{144} = 12[/tex]

the error was in not take the root of the number correctly

the student assumes that the root of 144 was equal to 72

9514 1404 393

Answer:

  -4/3

Step-by-step explanation:

Quadratic ax² +bx +c can be written in factored form as ...

  a(x -p)(x -q)

for zeros p and q. The expanded form of this is ...

  ax² -a(p+q)x +apq

Then the ratio of the constant term to the leading coefficient is ...

  c/a = (apq)/a = pq . . . . the product of the zeros

For your quadratic, the ratio c/a is -4/3, the product of the zeros.

_____

Additional comment

You will notice that the sum of zeros is ...

  -b/a = -(-a(p+q))/a = p+q

Answer:

[tex] \green{ \boxed{ \bf \: product \: of \: the \: zeros \: = - \frac{4}{3} }}[/tex]

Step-by-step explanation:

We know that,

[tex] \sf \: if \: \alpha \: and \: \beta \: \: are \: the \: zeroes \: of \: the \: \\ \sf \: polynomial \: \: \: \pink{a {x}^{2} + bx + c }\: \: \: \: then \\ \\ \small{ \sf \: product \: of \: zeroes \: \: \: \alpha \beta = \frac{constant \: term}{coefficient \: of \: {x}^{2} } } \\ \\ \sf \implies \: \pink{ \boxed{\alpha \beta = \frac{c}{a} }}[/tex]

Given that, the polynomial is :

[tex] \bf \: 3 {x}^{2} - 2x - 4[/tex]

so,

[tex] \sf \: so \: product \: of \: zeroes \: \: = \frac{ - 4}{3} = - \frac{4}{3} [/tex]

Answer:

56000 ft

Step-by-step explanation:

4000 steps a day.

7 days in a week.

2 ft per step

so, we calculate how many steps in a week

4000 × 7 = 28000

and then we calculate the distance by saying each of these steps is 2 ft

so,

28000 × 2 = 56000 ft

as a little extra thought :

there are 5280 ft in a mile.

so, the person walks

56000 / 5280 miles = 10.61 miles

in a week.

The triangle is missing and so i have attached it.

Answer:

x = 93°

Step-by-step explanation:

From the triangle attached, we can say that;

<SQP + <SQR = 180°

This is because sum of angles on a straight line equals 180°.

Secondly, we know that sum of angles in a triangle also equals 180°.

Thus;

<SQR + <QSR + <SRQ = 180

From the attached triangle, we see that;

<QSR = 35°

<SRQ = 58°

Thus;

<SQR + 35° + 58° = 180°

<SQR + 93° = 180°

<SQR = 180° - 93°

<SQR = 87°

From earlier on, we saw that;

<SQP + <SQR = 180°

Plugging in <SQR = 87°, we have;

<SQP + 87° = 180°

<SQP = 180° - 87°

<SQP = 93°

We are told in the question that <SQP is denoted by x.

Thus;

x = 93°

Answer:

The value of x is answer D: 93

Answer:

[tex]\frac{10}{21}[/tex]

Step-by-step explanation:

The LCM of 14, 21 and 6 is 42

We require to change the fractions to fractions with a denominator of 42

[tex]\frac{3(3)}{14(3)}[/tex] + [tex]\frac{2(2)}{21(2)}[/tex] + [tex]\frac{1(7)}{6(7)}[/tex]

= [tex]\frac{9}{42}[/tex] + [tex]\frac{4}{42}[/tex] + [tex]\frac{7}{42}[/tex] ← add the numerators, leaving the denominator

= [tex]\frac{9+4+7}{42}[/tex]

= [tex]\frac{20}{42}[/tex] ← divide both values by 2

= [tex]\frac{10}{21}[/tex] ← in simplest form

Answer:

I think it's 43 and 43 degrees. I just subtracted 180-94, got 86, and divided it so yea.

Answer:

x=-2

Step-by-step explanation:

Answer:

Since a = 2, the equation for the directrix line will be y = −2.

Step-by-step explanation:

Answer:

13.25×5+13, cost per day with a helmet.

Step-by-step explanation:

Numerical Expressions • Practice

Answer:

13.25×5+13, Per day without a helmet

Step-by-step explanation:

Answer:

20

Step-by-step explanation:

we know,

n(aUb)=n(a)+n(b)-n(a∩b)

so,

80=40+60-n(a∩b)

or, 80-(40+60)=-n(a∩b)

or, -n(a∩b)=80-100

or, -n(a∩b)=-20

or, n(a∩b)=20

Answer:

The answer is Angle 4 and Angle 3.

Answer:

It's answer is angle 4 and angle 3

Answer:

Option B, random sample

That should be the answer

Answer:

12

Step-by-step explanation:

We can say that two polygons are similar to each other if both of the polygons have the same shape and their corresponding sides are in the same proportion, hence the ratio of their corresponding sides are equal to each other.

As we can see from the problem since both of the polygons are similar, hence the ratio of their corresponding sides are in the same proportion, therefore let x represent the missing length, hence:

[tex]\frac{x}{15} =\frac{32}{40} =\frac{32}{40} \\\\\frac{x}{15} =\frac{32}{40} \\\\x=\frac{32*15}{40} \\\\x=12[/tex]

Answer:

4/9

Step-by-step explanation:

negative exponent means 1/...

so, this is

(32/243)^(4/10) = (32/243)^(2/5)

that means to the power of 2 and then pulling the 5th root.

so, let's pull the 5th root first, and then we square

(32/243)^(2/5) = (2⁵/3⁵)^(2/5) = (2/3)^2 = 4/9

Step-by-step explanation:

Explanation is in the attachment

Hope my answer is helpful to you ✌️❣️☪️❇️❇️☪️❣️✌️

Step-by-step explanation:

between -5 and -62

-7,-10,-60...so..on

between -1/7 and 1/8

Multiply any number by number with both the numbers but it should be multiplied by both the numbers:

for example:

-1/7×3/3= -3/21 ; 1/8×3/3= 3/24

So,

-2/21,2/24,1/24

hope it helps