Select all systems that are equivalent to this system:

7(2x-5)=21 What is x?

Over [174]

Answer:

x = 4

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Equality Properties

Step-by-step explanation:

Step 1: Define Equation

7(2x - 5) = 21

Step 2: Solve for x

Distribute 7: 2x - 5 = 3
Isolate x term: 2x = 8
Isolate x: x = 4

Step 3: Check

Plug in x into the original equation to verify it's a solution.

Substitute in x: 7(2(4) - 5) = 21
Multiply: 7(8 - 5) = 21
Subtract: 7(3) = 21
Multiply: 21 = 21

Here we see that 21 does indeed equal 21.

∴ x = 4 is the solution to the equation.

6 0

2 years ago

Describe how you would find 24+ 36 using mental math

FinnZ [79.3K]

Answer:

First add 6 and 4 together to get 10 now add 2 and 3 and 1 together which gets you 6 and add the zero from the 10 and you get 60

Step-by-step explanation:

6 0

3 years ago

PLEASE ANSWER ASAP I WILL MARK BRAINLY

Montano1993 [528]

Answer:

multiplication property of equality

Step-by-step explanation:

Since we are multiplying by the same amount on each side, we are using the multiplication property of equality

5 0

3 years ago

Read 2 more answers

How much will a train travel in 3/4 of an hour if the average speed is 50 mph?

Aloiza [94]

Since the train travels 50 miles in 1 hour, to find 3/4 of an hour:

3/4 * 50
75/2 miles

Hope this helps!

4 0

3 years ago

Read 2 more answers

Based on aâ poll, among adults who regret gettingâ tattoos, 18â% say that they were too young when they got their tattoos. Assum

Sergeeva-Olga [200]

Answer:

a) 20.44% probability that none of the selected adults say that they were too young to get tattoos.

b) 35.90% probability that exactly one of the selected adults says that he or she was too young to get tattoos.

c) 56.34% probability that the number of selected adults saying they were too young is 0 or 1.

d) No

Step-by-step explanation:

For each adult, there are only two possible outcomes. Either they say they were too young when they got their tattoos, or they don't say that. Each adult is independent of each other. So we use the binomial probability distribution 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.

18% say that they were too young when they got their tattoos.

This means that $p = 0.18$

Eight adults who regret getting tattoos are randomly selected

This means that $n = 8$

a. Find the probability that none of the selected adults say that they were too young to get tattoos.

This is P(X = 0).

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

$P(X = 0) = C_{8,0}.(0.18)^{0}.(0.82)^{8} = 0.2044$

20.44% probability that none of the selected adults say that they were too young to get tattoos.

b. Find the probability that exactly one of the selected adults says that he or she was too young to get tattoos.

This is P(X = 1).

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

$P(X = 1) = C_{8,1}.(0.18)^{1}.(0.82)^{7} = 0.3590$

35.90% probability that exactly one of the selected adults says that he or she was too young to get tattoos.

c. Find the probability that the number of selected adults saying they were too young is 0 or 1.

Either a. or b.

20.44 + 35.90 = 56.34

56.34% probability that the number of selected adults saying they were too young is 0 or 1.

d. It we randomly select 9 adults. Is 1 a significantly low number who day that they were too young to get tattoos?

Now $n = 9$

It is significantly low if it is more than 2.5 standard deviations below the mean.

The mean is $E(X) = np = 9*0.18 = 1.62$

The standard deviation is $\sqrt{V(X)} = \sqrt{n*p*(1-p)} = \sqrt{9*0.18*0.82} = 1.15$

1 > (1.62 - 2.5*1.15)

So the answer is no.

5 0

2 years ago