5. Anthony has 80 pine tree seedlings to plant in his meadow. He first plants one row of 12

The first three terms of a geometric sequence are shown below. x+3,-2x2-6x,4x3+12x2,.... What is the eighth term of the sequence

nika2105 [10]

So hmm is a geometric sequence, meaning, the next term is found by multiplying it by "something", namely the "common ratio"

now, if the next term is the product of the common ratio and the previous term, that means, if we divide the previous term by the next term, the quotient will then be the "common ratio", let's do that then

let's divide the 2nd term by the 1st term then

$\bf \cfrac{-2x^2-6x}{x+3}\implies \cfrac{-2x\underline{(x+3)}}{\underline{(x+3)}}\implies \boxed{-2x}\impliedby \textit{common ratio}\\\\
-----------------------------\\\\$

$\bf n^{th}\textit{ term of a geometric sequence}\\\\
a_n=a_1\cdot r^{n-1}\qquad 
\begin{cases}
n=n^{th}\ term\\
a_1=\textit{value of first term}\\
r=\textit{common ratio}\\
----------\\
a_1=x+3\\
n=8\\
r=-2x
\end{cases}
\\\\\\
a_8=(x+3)(-2x)^{8-1}\implies a_8=(x+3)(-2x)^7
\\\\\\
a_8=(x+3)(-2^7x^7)\implies a_8=(x+3)(-128x^7)
\\\\\\
a_8=-128x^8-384x^7$

8 0

2 years ago

Read 2 more answers

El Sr negron tiene que redactar una serie de cartas en su oficina. A Lourdes le toma 6 horas pasar todas las cartas. A su compañ

vodka [1.7K]

El Sr negron tiene que redactar una serie de cartas en su oficina. A Lourdes le toma 6 horas pasar todas las cartas. A su compañera rosabel, le toma 9 horas en realizar la misma tarea. Si ambas trabajan juntas para hacer todo el trabajo d ela oficina,

a. Cuánto tiempo le tomará a ambas realizar el trabajo?

Answer:

3.6 horas

Step-by-step explanation:

Sea el número total de horas que ambos trabajaron = T

Deje que la cantidad total de letras por las que pasaron = 1

De la pregunta, se nos dice:

Lourdes necesitó 6 horas para revisar las cartas.

Esto significa que, cada 1 hora, Lourdes revisaba 1/6 de las letras

Rosabel tardó 9 horas en leer las letras.

Esto significa que, cada 1 hora, Rosabel revisó 1/9 de las letras

Por lo tanto,

(1/6 × 1) T + (1/9 × 1) T = 1

(1/6 + 1/9) T = 1

(3 + 2/18) T = 1

(18/5) T = 1

5T / 18 = 1

Cruz multiplicar

5T = 18

T = 18/5

T = 3.6 horas

Por lo tanto, les tomó a ambas 3.6 horas hacer el trabajo.

7 0

2 years ago

In how many ways can you spell the word ROOM in the grid below? You can start on any letter R, then on each step you can step on

Zina [86]

Answer:

84? Not sure but pretty sure

Step-by-step explanation:

In a straight line, the word can only be spelled on the diagonals, and there are only two diagonals in each direction that have 2 O's.

If 90° and reflex turns are allowed, then the number substantially increases.

Corner R: can only go to the adjacent diagonal O, and from there to one other O, then to any of the 3 M's, for a total of 3 paths.

2nd R from the left: can go to either of two O's, one of which is the same corner O as above. So it has the same 3 paths. The center O can go to any of 4 Os that are adjacent to an M, for a total of 10 more paths. That's 13 paths from the 2nd R.

Middle R can go the three O's on the adjacent row, so can access the three paths available from each corner O along with the 10 paths available from the center O, for a total of 16 paths.

Then paths accessible from the top row of R's are 3 +10 +16 +10 +3 = 42 paths. There are two such rows of R's so a total of 84 paths.

6 0

1 year ago

Read 2 more answers

A ramp with a constant incline is made to connect a driveway to a front door. At a point 4 feet from the driveway, the height of

Mnenie [13.5K]

Answer:

3 inches up per foot across

Step-by-step explanation:

rate of change = difference of y / difference of x

R = (18 - 12) / ( 6-4) = 6 / 2 = 3 inch / foot

9 0