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3 years ago

I need help on this last question

Mathematics

1 answer:

zzz [600]3 years ago

8 0

Answer:

They are both correct but they rounded to different places. Scrooge rounded to the nearest whole number while Bon rounded to the nearest tenth.

Step-by-step explanation:

Scrooge rounded up to the next whole number which was three because the tenth place value was 5 or greater.

While Bob on the other hand rounded to the nearest tenth. Which resulted in the number going down because the number in the hundredth place value was less than 5.

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Tara standing 20 feet from a tree and the angle of elevation is 72°. About how tall is the tree?

Zinaida [17]

Answer:

Approx 61.554 feet

Step-by-step explanation:

Since we are dealing with the opposite and adjacent sides, we will use tangent as our ratio.

Since the angle of elevation is 72 degrees, the left side of our equation is $tan(72)$ .

The right side of the equation is opposite over adjacent.

$x/20$

Set these equal to each other.

$tan(72) = x/20$

Simplify.

$20 tan(72)=x$

$20(3.078) = x$

x is approximately 61.554.

4 0

3 years ago

Solve for x, show all of your work: -2x – 4 < 10

NNADVOKAT [17]

3 0

4 years ago

A school bought pens, each costing $1, and pencils, each costing $0.5. The cost of the whole purchase was $220. How many pens an

Aleks [24]

Answer:

<u>The number of pens = 120 and the number of pencils = 200</u>

Step-by-step explanation:

Let the number of pens x, and the number of pencils is y

the cost of one pen $1, and the cost of one pencil $0.5

The cost of the whole purchase was $220

1 * x + 0.5 * y = 220

x + 0.5 y = 220 ⇒ eq.(1)

there were 80 more pencils than pens

y - x = 80 ⇒ eq.(2)

from eq.(2) x = y - 80

By substitution with x from the last equation at eq.(1)

∴ (y - 80) + 0.5 y = 220

1.5y = 220 + 80 = 300

y = 300/1.5 = 200

x = y - 80 = 200 - 80 = 120

<u>So, the number of pens = 120 and the number of pencils = 200</u>

7 0

3 years ago

Helene is finding the sum (9 10i) (–8 11i). She rewrites the sum as (–8 11)i (9 10)i. Which statement explains the property of a

Andreyy89

She made the mistake of grouping unlike terms and factorizing.

Given that

Helene is finding the sum (9 + 10i) + (–8 + 11i).

She rewrites the sum as (–8 + 11)i + (9 + 10)i.

We have to determine

Which statement explains the property of addition that she made an error in using?

According to the question

The mistake she did is in the second term distributing.

(9+10i) is not equal to (9+10)i

Similarly (-8+11i) is not equal to (-8+11)i.

The correct method she should have done is given below;

Grouping real terms together and imaginary terms together and finding the sum is,

$\rm = (9 + 10i) + (-8 + 11i)\\\\= 9+10i-8+11i\\\\= (9-8) +(10i+11i)\\\\=1+21i$

Hence, she made the mistake of grouping unlike terms and factorizing.

To know more about Complex Number click the link given below.

brainly.com/question/10078818

6 0

3 years ago

Let y in the form of a + ib, where a and b are real numbers, be the cubic roots of a complex number z 20, where z =2 4+i3. Find

GalinKa [24]

The possible values of a + b are 0.89, 3.01 and -3.9

<h3>How to determine the value of a + b?</h3>

The given parameters are:

y = a + ib

z = 24 + i3

Where:

y = ∛z

Take the cube of both sides

y³ = z

Substitute the values for y and z

(a + ib)³ = 24 + i3

Expand

a³ + 3a²(ib) + 3a(ib)² + (ib)³ = 24 + i3

Further, expand

a³ + i3a²b + i²3ab² + i³b³ = 24 + i3

In complex numbers;

i² = -1 and i³= -i

So, we have:

a³ + i3a²b + (-1)3ab² -ib³ = 24 + i3

Further expand

a³ + i3a²b - 3ab² - ib³ = 24 + i3

By comparing both sides of the equation, we have:

a³ - 3ab² = 24

i3a²b - ib³ = i3

Divide through by i

3a²b - b³ = 3

So, we have:

a³ - 3ab² = 24

3a²b - b³ = 3

Using a graphing tool, we have:

(a,b) = (-1.55, 2.44), (2.89,0.12) and (-1.34,-2.56)

Add these values

a + b = 0.89, 3.01 and -3.9

Hence, the possible values of a + b are 0.89, 3.01 and -3.9