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2 years ago

What is the sum of the first eight terms of the geometric series?

Mathematics

1 answer:

const2013 [10]2 years ago

8 0

-4 + 20- 100 + 500 - 2500 + 12,500 - 62,500 + 312,500 = 260,416

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What are the exact solutions of x2 − 5x − 7 = 0, where x equals negative b plus or minus the square root of b squared minus 4 ti

Marat540 [252]

Answer:

$x = \frac{5 + \sqrt{53}}{2}$ or $x = \frac{5 - \sqrt{53}}{2}$

Step-by-step explanation:

Given

$x^2 - 5x - 7 = 0$

Required

Solve for x using:

$x = \frac{-b \± \sqrt{b^2 - 4ac}}{2a}$

First, we need to identify a, b and c

The general form of a quadratic equation is:

$ax^2 + bx + c = 0$

So, by comparison with $x^2 - 5x - 7 = 0$

$a = 1$ $b = -5$ $c = -7$

Substitute these values of a, b and c in

$x = \frac{-b \± \sqrt{b^2 - 4ac}}{2a}$

$x = \frac{-(-5) \± \sqrt{(-5)^2 - 4 * 1 * -7}}{2 * 1}$

$x = \frac{5 \± \sqrt{25 +28}}{2}$

$x = \frac{5 \± \sqrt{53}}{2}$

Split the expression to two

$x = \frac{5 + \sqrt{53}}{2}$ or $x = \frac{5 - \sqrt{53}}{2}$

To solve further in decimal form, we have

$x = \frac{5 + 7.28}{2}$ or $x = \frac{5 - 7.28}{2}$

$x = \frac{12.28}{2}$ or $x = \frac{-2.28}{2}$

$x = 6.14$ or $x = -1.14$

4 0

3 years ago

Evaluate the expression when d = 20 and v = 19 20v + 12d - 6v

Alexeev081 [22]

D = 20 , v = 19
20v + 12d - 6v
= 20 (19) + 12 (20) - 6 (19)
= 380 + 240 - 114
= 620 - 114
= 506
When d = 20 and v = 19
20v + 12d - 6v = 506

6 0

2 years ago

Read 2 more answers

Write 56\90 as a decimal

Evgen [1.6K]

Answer:

0.62

Step-by-step explanation:

divide 56 by 90

Hope this helps :)

7 0

2 years ago

Read 2 more answers

Gemma and Leah are both jewelry makers. Gemma made 106 beaded necklaces. Leah made 39 more necklaces than Gemma.

timofeeve [1]

Answer:

Gemma made $34 more than Leah.

Step-by-step explanation:

Gemma made number of beaded necklaces = 106

Leah made 39 more necklaces than Gemma.

Leah made number of beaded necklaces = 106 + 39 = 145

a. There are 104 beads on each necklace.

The total number of beads used altogether

= (106 × 104) + (145 × 104)

= 11,024 + 15,080

= 26,104

b. Gemma sold her 106 necklaces for = $14

Total price of her necklaces = 106 × 14

= $1,484

Leah sold her 145 necklaces for = $10

Total price of her necklaces = 145 × 10

= $1,450

Difference in Gemma and Leah's amount = 1484 - 1450 = $34.00

Therefore, Gemma made $34.00 more money than Leah.

6 0

3 years ago

Please please help ASAP please please I’ll mark you as a branlist

wel

Answer:

4°

Step-by-step explanation:

Since it is said that the angles are corresponding angles so we know that corresponding angles are equal then,

<1 = <2

3x - 7 ° = x - 1°

3x - x = 7° - 1°

2x = 8°

x = 8° / 2

Therefore x = 4°

Hope it will help you :)

5 0

2 years ago