3 years ago

Which expression defines the given series for seven terms? 8 + 13 + 18 + . . .

1 answer:

7 0

The given question is 8+13+18+...... which is in arithmetic progression . And for arithmetic series, we have to use the following formula for nth term .

$a_{n} = a + (n-1)d$

Here a =8 , d=5

So we get

$a_{n} = 8+(n-1)5 = 5n +3$

And the required expression for n=7 is

$\sum_{n=1}^{7}(5n+3)$

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In the standard (x,y) coordinate plane, what is the slope of the line 4x+7y=9?

o-na [289]

Answer: -4/7

Step-by-step explanation:

To find the slope, let's change the equation to slope-intercept form.

$4x+7y=9$ [subtract both sides by 4x]

$7y=-4x+9$ [divide both sides by 7]

$y=-\frac{4}{7}x+\frac{9}{7}$

Now, we know the slope is -4/7.

5 0

3 years ago

Plz help and explain

Firdavs [7]

Id say the first one because the points just touch down

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3 years ago

Karina pays $1.92 for pencil erasers. the erasers cost $0.08 each. how many erasers does she buy?

horrorfan [7]

1.92 / 0.08 = 24.....Karina bought 24 erasers

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3 years ago

If a line with the slope -2 crosses the y-axis at (0,3),what is the equation of the line

gregori [183]

The equation of the line is y=-2x+3.

6 0

4 years ago

I've tried to get the answer for this 13 times now (not joking), plzzz help: write a formula that represents the number of peopl

gtnhenbr [62]

Answer:

2820 seats
aₙ = 3n + 9

Step-by-step explanation:

This is an AP with:

The first term a₁ = 12
Common difference d = 3
Number of terms n = 40

Number of the seats:

Sₙ = 1/2*n(a₁ + aₙ) = 1/2n(2a₁ + (n - 1)d)
S₄₀ = 1/2*40(12*2 + 39*3) = 2820 seats

Formula of nth term:

aₙ = a₁ + (n - 1)d
aₙ = 12 + (n - 1)*3 = 12 + 3n - 3 = 3n + 9
aₙ = 3n + 9

6 0

3 years ago