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3 years ago

Solve the equation 2x^{2}+9x-1=x to the nearest 10th

Mathematics

1 answer:

Scilla [17]3 years ago

4 0

Answer:

2x2+9x−1=x

Step 1: Subtract x from both sides.

2x2+9x−1−x=x−x

2x2+8x−1=0

Step 2: Use quadratic formula with a=2, b=8, c=-1.

−b±√b2−4ac

−(8)±√(8)2−4(2)(−1)

2(2)

−8±√72

x=−2+

√2 or x=−2+

−3

√2

Step-by-step explanation:

This is what I got but I'm not 100% positive. I checked it on a calculator and it seemed to check out.

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The area of a rectangular park is 3/5 square mile. The length of the park is 7/8 mile. What is the width of the park?

lesya [120]

I hope this helps you

Area = width. length

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w=3/5.8/7

w=24/35

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2 years ago

The number 320 million written in scientific notation would be _____.

lisabon 2012 [21]

The scientific notation: $a\cdot10^n\ where\ 1\leq a < 10\ and\ n\in\mathbb{Z}$

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2 years ago

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The time it takes a student to walk from the dorm to the chemistry lab follows roughly a Normaldistribution with a mean of 20 mi

creativ13 [48]

Answer:

95.15%

Step-by-step explanation:

We have that the mean (m) is equal to 20, the standard deviation (sd) 3

They ask us for P (x <25)

For this, the first thing is to calculate z, which is given by the following equation:

z = (x - m) / sd

We have all these values, replacing we have:

z = (25 - 20) / (3)

z = 1.66

With the normal distribution table (attached), we have that at that value, the probability is:

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Which means that the probability that it arrives before 25 minutes is 95.15%

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3 years ago

Wendy is standing 60 feet away from a tree. Her eyes are 5 feet above the ground. She sees a bird hovering above a tree. The ang

Gennadij [26K]

The bird is 17 feet above the tree.

<u>Explanation:</u>

We need to think of this in terms of right triangles. If Wendy is 60 feet from a tree, the base of the right triangle is 60 feet. The height of the tree is the height of the right triangle. The angle of elevation is the one from the ground at her feet to the top of the tree and then to the bird. Let's start with the top of the tree first.

She's 60 feet away, we have the angle of elevation as 25 degrees, and we are looking for the height of the tree. In regards to the angle, the base of 60 is adjacent, and the height of the tree is opposite. The tangent ratio is height / base.

Let x be the height of the tree.

So,

$tan (25) = \frac{x}{60}$

$60 tan(25) = x\\\\x = 27.9 feet$

x is approximately 28 feet

Since, Wendy's eyes are 5 feet above the ground, the height of the tree becomes

28 + 5 = 33 feet

Let y be the height of the bird in the air

$tan(37) = \frac{y}{60} \\\\60 tan(37) = y\\\\y = 45.2 feet$

y is approximately 45 feet

Since, Wendy's eyes are 5 feet above the ground, the height of the tree becomes

45 + 5 = 50 feet

To know how far above the tree that bird is

50 - 33 = 17 feet

Therefore, the bird is 17 feet above the tree.

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3 years ago