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3 years ago

Which step should be performed first in the expression? Then simplify the expression. 5(-3)+6

Mathematics

1 answer:

BabaBlast [244]3 years ago

4 0

Answer:

5(-3) would be the first step

Step-by-step explanation:

5 * -3 = -15

-15 + 6 = -9

-9 is the answer

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A plane begins to descend from a height of 202 meters. The plane decreases in altitude at an average rate of 1.8 meters per seco

stepladder [879]

The plane starts at 202 m.
All altitudes are in meters.
After 1 second, it is at 202 - 1.8
After 2 seconds, it is at 202 - 1.8 * 2
After 3 seconds, it is at 202 - 1.8 * 3
etc.
After x seconds, it is at 202 - 1.8 * x

202 - 1.8 * x is the same as 202 - 1.8x

Answer: F. t(x) = 202 - 1.8x

3 0

3 years ago

A pyramid has a square base of length 8cm and a total surface area of 144cm². Find the volume of the pyramid. (Please use Pythag

Sveta_85 [38]

Answer:

$\displaystyle V_{ \text{pyramid}}= 64 \: {cm}^{3}$

Step-by-step explanation:

we are given surface area and the length of the square base

we want to figure out the Volume

to do so

we need to figure out slant length first

recall the formula of surface area

$\displaystyle A_{\text{surface}}=B+\dfrac{1}{2}\times P \times s$

where B stands for Base area

and P for Base Parimeter

$\sf\displaystyle \: 144=(8 \times 8)+\dfrac{1}{2}\times (8 \times 4) \times s$

now we need our algebraic skills to figure out s

simplify parentheses:

$\sf\displaystyle \: 64+\dfrac{1}{2}\times32\times s = 144$

reduce fraction:

$\sf\displaystyle \: 64+\dfrac{1}{ \cancel{ \: 2}}\times \cancel{32} \: ^{16} \times s = 144 \\ 64 + 16 \times s = 144$

simplify multiplication:

$\displaystyle \: 16s + 64 = 144$

cancel 64 from both sides;

$\displaystyle \: 16s = 80$

divide both sides by 16:

$\displaystyle \: \therefore \: s = 5$

now we'll use Pythagoras theorem to figure out height

according to the theorem

$\displaystyle \: {h}^{2} + (\frac{l}{2} {)}^{2} = {s}^{2}$

substitute the value of l and s:

$\displaystyle \: {h}^{2} + (\frac{8}{2} {)}^{2} = {5}^{2}$

simplify parentheses:

$\displaystyle \: {h}^{2} + (4 {)}^{2} = {5}^{2}$

simplify squares:

$\displaystyle \: {h}^{2} + 16 = 25$

cancel 16 from both sides:

$\displaystyle \: {h}^{2} = 9$

square root both sides:

$\displaystyle \: \therefore \: {h}^{} = 3$

recall the formula of a square pyramid

$\displaystyle V_{pyramid}=\dfrac{1}{3}\times A\times h$

where A stands for Base area (l²)

substitute the value of h and l:

$\sf\displaystyle V_{ \text{pyramid}}=\dfrac{1}{3}\times \{8 \times 8 \}\times 3$

simplify multiplication:

$\sf\displaystyle V_{ \text{pyramid}}=\dfrac{1}{3}\times 64\times 3$

reduce fraction:

$\sf\displaystyle V_{ \text{pyramid}}=\dfrac{1}{ \cancel{ 3 \: }}\times 64\times \cancel{ \: 3}$

hence,

$\sf\displaystyle V_{ \text{pyramid}}= 64 \: {cm}^{3}$

8 0

2 years ago

Plz help me with this

8090 [49]

Answer:

8.216 put a line on top of the six because it's repeating

Step-by-step explanation:

4 0

3 years ago

Read 2 more answers

Classify the following triangle. check all that apply

Vsevolod [243]

Answer is acute and scalene

This triangle is acute since all angles (51, 79, 70) are all less than 90 degrees. It is a scalene triangle as well since none of the sides (10, 12.1 , 11) are equal to each other.

Here are the other definitions to help you in the future

equilateral- All sides are the same. Right - Has one right angle. Obtuse - Has an angle more than 90 degrees. Isosceles - Only two sides are the same. One is different.

5 0

3 years ago

Read 2 more answers

To determine whether they need to hire extra help for the holiday season, the managers of a railroad company want to estimate ho

nadezda [96]

Answer:

Step-by-step explanation:

Data provided in the question:

Standard error = 1.5 minutes ( ∵ number are repetitive 1.51.5 )

Standard deviation = 9 minutes ( ∵ number are repetitive 99 )

Now,

Standard error = ( Standard deviation ) ÷ √n

Here,

n is the sample size

Therefore,

on substituting the respective values, we get

1.5 = 9 ÷ √n

√n = 9 ÷ 1.5

√n = 6

n = 6² = 36

3 0

3 years ago