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2 years ago

Solve the equation by using the quadratic formula. 8x2 – 2x - 15 =0

Mathematics

1 answer:

ddd [48]2 years ago

4 0

Answer:

x = 3/2 or x = -5/4

Step-by-step explanation:

Solve for x over the real numbers:

8 x^2 - 2 x - 15 = 0

Using the quadratic formula, solve for x.

x = (2 ± sqrt((-2)^2 - 4×8 (-15)))/(2×8) = (2 ± sqrt(4 + 480))/16 = (2 ± sqrt(484))/16:

x = (2 + sqrt(484))/16 or x = (2 - sqrt(484))/16

Simplify radicals.

sqrt(484) = sqrt(4×121) = sqrt(2^2×11^2) = 2×11 = 22:

x = (2 + 22)/16 or x = (2 - 22)/16

Evaluate (2 + 22)/16.

(2 + 22)/16 = 24/16 = 3/2:

x = 3/2 or x = (2 - 22)/16

Evaluate (2 - 22)/16.

(2 - 22)/16 = -20/16 = -5/4:

Answer: x = 3/2 or x = -5/4

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RoseWind [281]

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Of 100 students,65 are members of a mathematics club and 40 are members of a physics club. if 10 are members of neither club the

alexandr1967 [171]

a. 15 students are members of both clubs

b. 50 students only are members of the mathematics club

c. 25 students only are members of the physics club

Step-by-step explanation:

The given is:

There are 100 students
65 are members of a mathematics club
40 are members of a physics club
10 are members of neither club

We need to find how many students are members of

a. both clubs?

b. only mathematics club

c. only physics club

∵ The total number of students = 100

∵ 10 are members of neither club

- Subtract 10 from 100 to find the members of the mathematics

club or the physics club

∵ 100 - 10 = 90

∴ There are 90 members of the mathematics club or physics club

∴ n(mathematics or physics) = 90

∵ 65 students are members of a mathematics club

∵ n(mathematics) = 65

∵ 40 students are members of a physics club

∴ n(physics) = 40

∵ n(mathematics or physics) = n(mathematics) + n(physics) - n(both)

∴ 90 = 65 + 40 - n(both)

∴ 90 = 105 - n(both)

- Add n(both) to each side

∴ n(both) + 90 = 105

- Subtract 90 from each side

∴ n(both) = 15

∴ 15 students are members of both clubs

a. 15 students are members of both clubs

∵ 65 students are members of the mathematics club

∵ 15 of them are members of the physics club

∴ n(mathematics only) = 65 - 15 = 50

∴ 50 students only are members of the mathematics club

b. 50 students only are members of the mathematics club

∵ 40 students are members of the physics club

∵ 15 of them are members of the mathematics club

∴ n(physics only) = 40 - 15 = 25

∴ 25 students only are members of the physics club

c. 25 students only are members of the physics club

Learn more:

You can learn more about word problems in brainly.com/question/8907574

#LearnwithBrainly

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3 years ago

Help? im confused plss! Find the area of the regular polygon with the given radius or apothem

Snezhnost [94]

Answer:

50 cm²

Step-by-step explanation:

Given that the regular polygon is a square, there are multiple ways you can jump directly to the answer. Perhaps the simplest is to use the formula for the area of a rhombus:

A = 1/2(d1)(d2)

where d1 and d2 are the lengths of the diagonals. Here, we see that half the diagonal is 5 cm, so the area is ...

A = (1/2)(10 cm)(10 cm) = 50 cm² . . . . area of the polygon

Alternate solution

If you want to use the radius and the number of sides in a formula, you can consider the area of each triangle formed by radii and a side. That triangle has area ...

A = 1/2r²sin(α)

where r is the radius and α is the central angle. For an n-sided polygon, the area is the sum of n of these triangles, and the central angle is 360°/n. Then the polygon area is ...

A = n/2·r²·sin(360°/n)

For n = 4 and r = 5 cm, the area is ...

A = (4/2)(5 cm)²(sin(360°/4)) = 2(5 cm)²(1) = 50 cm² . . . . area of square

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Additional comment

The formula is somewhat different if you start with the length of the apothem. One way to find the area is using the above formula and the relation between the radius and apothem:

r = a·sec(180°/n)

Another formula uses the apothem directly:

A = n·a²·tan(180°/n)

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Aleks04 [339]

Answer:

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Step-by-step explanation:

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Alenkinab [10]

Okay, i went with a rectangle, if the rectangle base is 12 and the height is 6 then it would be 12*6 + 12*6 + 12*6= 216 now the ratio is easy , 72:72 because that's what makes up the 12*6 and because there is 3 it's 72 two times now for part b 5 x 10 so that is the height and length so now what you want to do is do what you did the second time so it would be 72:50.
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