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3 years ago

How do you find the missing number of a perfect square trinomial? 25x^2 - 60x + ___

Mathematics

1 answer:

Harrizon [31]3 years ago

4 0

Answer:

Step-by-step explanation:

Compare what you have to the square ...

(a +b)^2 = a^2 +2ab +b^2

Your "a" is √(25x^2) = 5x

Your "2ab" is -60x. Since you know "a", you can find "b".

2ab = -60x

2(5x)b = -60x . . . . . . . substitute for "a"

b = -60x/(10x) = -6

Then the missing term is b^2 = (-6)^2 = 36.

Your trinomial is ...

25x^2 -60x +<u>36</u>

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Please help me w this question!! I’m so confused!!

expeople1 [14]

Answer:

coefficient is 128 and exponent is 8

Step-by-step explanation:

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3 years ago

1. A luge race is very dangerous, and a crash can cause serious injuries. The league requires anyone who has a crash to have a t

antiseptic1488 [7]

Answer:

0.7061 = 70.61% probability she will have her first crash within the first 30 races she runs this season

Step-by-step explanation:

For each race, there are only two possible outcomes. Either the person has a crash, or the person does not. The probability of having a crash during a race is independent of whether there was a crash in any other race. This means that the binomial probability distribution is used to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

A certain performer has an independent .04 probability of a crash in each race.

This means that $p = 0.04$

a) What is the probability she will have her first crash within the first 30 races she runs this season

This is:

$P(X \geq 1) = 1 - P(X = 0)$

When $n = 30$

We have that:

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{30,0}.(0.04)^{0}.(0.96)^{30} = 0.2939$

$P(X \geq 1) = 1 - P(X = 0) = 1 - 0.2939 = 0.7061$

0.7061 = 70.61% probability she will have her first crash within the first 30 races she runs this season

7 0

2 years ago

Find the indicated probability. The weekly salaries of teachers in one state are normally distributed with a mean of $490 and a

Alecsey [184]

Given Information:

Mean weekly salary = μ = $490

Standard deviation of weekly salary = σ = $45

Required Information:

P(X > $525) = ?

Answer:

P(X > $525) = 21.77%

Step-by-step explanation:

We want to find out the probability that a randomly selected teacher earns more than $525 a week.

$P(X > 525) = 1 - P(X < 525)\\\\P(X > 525) = 1 - P(Z < \frac{x - \mu}{\sigma} )\\\\P(X > 525) = 1 - P(Z < \frac{525 - 490}{45} )\\\\P(X > 525) = 1 - P(Z < \frac{35}{45} )\\\\P(X > 525) = 1 - P(Z < 0.78)\\\\$

The z-score corresponding to 0.78 from the z-table is 0.7823

$P(X > 525) = 1 - 0.7823\\\\P(X > 525) = 0.2177\\\\P(X > 525) = 21.77 \%$

Therefore, there is 21.77% probability that a randomly selected teacher earns more than $525 a week.

How to use z-table?

Step 1:

In the z-table, find the two-digit number on the left side corresponding to your z-score. (e.g 0.7, 2.2, 1.5 etc.)

Step 2:

Then look up at the top of z-table to find the remaining decimal point in the range of 0.00 to 0.09. (e.g. if you are looking for 0.78 then go for 0.08 column)

Step 3:

Finally, find the corresponding probability from the z-table at the intersection of step 1 and step 2.

3 0

3 years ago

Help for good luck<br> and a lot of money

Alex777 [14]

1= 12.2
8=97.6
and for the last one the answer is 10 :))

5 0

2 years ago

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Yolanda bought .5 pounds of grapes for $3.99. Find the unit rate

Airida [17]