Ask question

Ask question

All categories

goldfiish [28.3K]

3 years ago

5

Find the sum of a finite arithmetic sequence from n = 1 to n = 10, using the expression 3n − 8.

1 answer:

maw [93]3 years ago

8 0

Answer:

The answer is 85

Step-by-step explanation:

The equation used to find the sum of an arithmetic series is: (n/2) * (a1 + an).

n in this case is 10 (the number of numbers in the series)

an is 22 (plug in 10 to the expression 3n-8)

and a1 is -5 (plug in 1 to the expression 3n-8)

so when you plug everything in to the final equation, you get

(10/2) * (-5 + 22)

5 * 17

85

You might be interested in

17.5 how to make this into a fraction

BARSIC [14]

Take the .5 of the 17.5 and convert it to a fractin.
we know .5 is equal to 50% or 1/2

now we have a mixed number $17 \frac{1}{2}$

in order to convert it into an improper fraction you need to multiply the whole number by the denominator and then add the numerator all while keeping the denominator constant.

$W \frac{N}{D} = \frac{(W*D)+N}{D}$

so $17 \frac{1}{2}= \frac{(17*2)+1}{2}= \frac{35}{2}$

5 0

3 years ago

Read 2 more answers

1. Write the standard form of the line that passes through the given points. (7, -3) and (4, -8)

Sveta_85 [38]

Answer:

1. $-5x+3y+44=0$

2. $2x+y-2=0$

3. $2x+y-4=0$

Step-by-step explanation:

Standard form of a line is $Ax+By+C=0$ .

If a line passing through two points then the equation of line is

$y-y_1=m(x-x_1)$

where, m is slope, i.e., $m=\dfrac{y_2-y_1}{x_2-x_1}$ .

1.

The line passes through the points (7,-3) and (4,-8). So, the equation of line is

$y-(-3)=\dfrac{-8-(-3)}{4-7}(x-7)$

$y+3=\dfrac{-5}{-3}(x-7)$

$y+3=\dfrac{5}{3}(x-7)$

$3(y+3)=5(x-7)$

$3y+9=5x-35$

$-5x+3y+9+35=0$

$-5x+3y+44=0$

Therefore, the required equation is $-5x+3y+44=0$ .

2.

We need to find the equation of the line, in standard form, that has a y-intercept of 2 and is parallel to $2 x + y =-5$ .

Slope of the line : $m=\dfrac{-\text{Coefficient of x}}{\text{Coefficient of y}}=\dfrac{-2}{1}=-2$

Slope of parallel lines are equal. So, the slope of required line is -2 and it passes through the point (0,2).

Equation of line is

$y-2=-2(x-0)$

$y-2=-2x$

$2x+y-2=0$

Therefore, the required equation is $2x+y-2=0$ .

3.

We need to find the equation of the line, in standard form, that has an x-intercept of 2 and is parallel to $2x + y =-5$ .

From part 2, the slope of this line is -2. So, slope of required line is -2 and it passes through the point (2,0).

Equation of line is

$y-0=-2(x-2)$

$y=-2x+4$

$2x+y-4=0$

Therefore, the required equation is $2x+y-4=0$ .

5 0

3 years ago

Find all the values of × for which the statement is true.

andrew-mc [135]

X=3 , -3

Shsjdhshajbahe

5 0

3 years ago

What is the slope of a line that passes through the points (4,3) and (-7,1)?

Andreyy89

Answer:

-2/3

Step-by-step explanation:

If you use the formula y2-y1/x2-x1 your answer will be -2/3

5 0

2 years ago

Read 2 more answers

HELP PLZS FAST BRAINIEST

kirill115 [55]

Answer:

x=-2, y=-2. (-2, -2).

Step-by-step explanation:

2x-5y=6

-2x+10y=-16

-------------------

5y=-10

y=-10/5=-2

2x-5(-2)=6

2x+10=6

2x=6-10

2x=-4

x=-4/2=-2

3 0

2 years ago

Read 2 more answers