I need help ASAP!!!!!!

PLEASE HELP ILL MARK BRAINLIEST !!!

Alexus [3.1K]

Answer:

a) the common difference is 20

b) $x_8=115 , x_{12}=195$

c) the common difference is -13

d) $a_{12}=52, a_{15}=13$

Step-by-step explanation:

a) what is the common difference of the sequence xn

Looking at the table, we get x_3=16, x_4=36 and x_5= 56

Deterring the common difference by subtracting x_4 from x_3 we get

36-16 =20

So, the common difference is 20

b) what is x_8? what is x_12

The formula used is: $x_n=x_1+(n-1)d$

We know common difference d= 20, we need to find $x_1$

Using $x_3=16$ we can find $x_1$

$x_n=x_1+(n-1)d\\x_3=x_1+(3-1)d\\15=x_1+2(20)\\15=x_1+40\\x_1=15-40\\x_1=-25$

So, We have $x_1 = -25$

Now finding $x_8$

$x_n=x_1+(n-1)d\\x_8=x_1+(8-1)d\\x_8=-25+7(20)\\x_8=-25+140\\x_8=115$

So, $\mathbf{x_8=115}$

Now finding $x_{12}$

$x_n=x_1+(n-1)d\\x_{12}=x_1+(12-1)d\\x_{12}=-25+11(20)\\x_{12}=-25+220\\x_{12}=195$

So, $\mathbf{x_{12}=195}$

c) what is the common difference of the sequence $a_m$

Looking at the table, we get a_7=104, a_8=91 and a_9= 78

Deterring the common difference by subtracting a_7 from a_8 we get

91-104 =-13

So, the common difference is -13

d) what is a_12? what is a_15?

The formula used is: $a_n=a_1+(n-1)d$

We know common difference d= -13, we need to find $a_1$

Using $a_7=104$ we can find $x_1$

$a_n=a_1+(n-1)d\\a_7=a_1+(7-1)d\\104=a_1+7(-13)\\104=a_1-91\\a_1=104+91\\a_1=195$

So, We have $a_1 = 195$

Now finding $a_{12}$ , put n=12

$a_n=a_1+(n-1)d\\a_{12}=a_1+(12-1)d\\a_{12}=195+11(-13)\\a_{12}=195-143\\a_{12}=52$

So, $\mathbf{a_{12}=52}$

Now finding $a_{15}$ , put n=15

$a_n=a_1+(n-1)d\\a_{15}=a_1+(15-1)d\\a_{15}=195+14(-13)\\a_{15}=195-182\\a_{15}=13$

So, $\mathbf{a_{15}=13}$

5 0

3 years ago

Josh simplified 4x - 8x ÷ 2 and said the answer was -2x. What was josh's error? What should his answer have been?

Svetradugi [14.3K]

Answer:

see explanation

Step-by-step explanation:

Given

4x - 8x ÷ 2

Under the rules of PEMDAS , division must be performed before subtraction.

Hence

4x - 8x ÷ 2 = 4x - 4x ← dividing - 8x by 2, then

4x - 4x = 0 ← correct answer

6 0

3 years ago

What is the length of side AC of the triangle? Pls hurry

kodGreya [7K]

Answer:

Step-by-step explanation:

According to the first triangle inequality theorem, the lengths of any two sides of a triangle must add up to more than the length of the third side. This means that you cannot draw a triangle that has side lengths 2, 7 and 12, for instance, since 2 + 7 is less than 12.

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3 years ago

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Simple interest I in dollars is calculated using the formula I=prt, where p represents the principal, or amount in dollars tha

Sergeeva-Olga [200]

and we do this one the same way as the other.

$\bf ~~~~~~ \textit{Simple Interest Earned} \\\\ I = Prt\qquad \begin{cases} I=\textit{interest earned}\dotfill&\$540\\ P=\textit{original amount deposited}\dotfill & \$4800\\ r=rate\to 4.5\%\to \frac{4.5}{100}\dotfill &0.045\\ t=years \end{cases} \\\\\\ 540=(4800)(0.045)t\implies \cfrac{540}{(4800)(0.045)}=t\implies 2.5=t$

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3 years ago

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Find the product of (x-7)^2 and explain how it demonstrates the closure property of multiplication

iogann1982 [59]

A. x²-14x+49; is a polynomial

Step-by-step explanation:

(x-7)² can be written as (x-7)(x-7)

Expanding the expression

x(x-7)-7(x-7)

x²-7x-7x+49

x²-14x+49 ⇒⇒A quadratic function, which is a polynomial of degree 2

This function demonstrates the closer property of multiplication in that the change in order of multiplication does not change the product. This is called commutative property.

(x-7)(x-7)

-7(x-7)+x(x-7)

-7x+49+x²-7x

x²-14x+49

Learn More

Polynomials :brainly.com/question/9601478

Keywords : product, closure property of multiplication,

#LearnwithBrainly

4 0

3 years ago