Evaluate the expression. (132−122)÷5 The value of the expression__

Morgan, Dakota and Taylor showed their work solving the equation 7x+5x+1=73. Identify the student with the invalid first step an

antoniya [11.8K]

Answer:

Step-by-step explanation:

Given the equation solved by Morgan, Dakota and Taylor expressed as 7x+5x+1=73, to get the value of x, the valid steps are as shown;

7x+5x+1=73

take the sum of 7x and 5x

12x+ 1 = 73

subtract 1 from both sides

12x+1-1 = 73-1

12x = 72

Divide both sides by 12

12x/12 = 72/12

x = 6

Based on the calculation above, the students with invalid first step is Dakota.

Dakota added 5x with 1 to get 6x which is an invalid step because 1 is not attached to a variable x. A function cannot be added to a constant hence making his first step invalid.

8 0

3 years ago

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The total cost to go horseback riding is x dollars per hour plus a $3 fee for renting a helmet. Write an expression to represent

solniwko [45]

The answer is 15x + 15

Each person needs to pay x dollars per hour, and also 3 dollars for a helmet

Let us convert this into a pseudo-expression:

1 person = (x dollars) x (y hours) + 3 dollars

Now, it says that there are 5 people, so we need to multiply both sides by 5

5 people = 5 x (x dollars) x (yhours) + 3 x 5 dollars

Furthermore, it says that each person wants to go horseback riding for 3 hours:

5 people = 5(x dollars) x (3 hours) + 15 dollars

Now, we just need to convert this into an expression

5 people = 5(x)(3) + 15

5 people = 15x+15

They want the expression for cost, so we just need to give them

15x + 15

5 0

3 years ago

Rewrite the equation y – 4x = –9 in slope-intercept form.

torisob [31]

Answer: y=4x-9

explanation: move the -4x over to the other side and it becomes positive 4x and -9 stays the same.

4 0

3 years ago

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Subtracting Two Vectors not at the Origin

aev [14]

Answer:

5, 3

Step-by-step explanation:

5 0

3 years ago

An insurance company selected a random sample of 500 clients under 18 years of age and found that 180 of them had had an acciden

Butoxors [25]

Answer:

a) The pooled proportion is p=0.3.

b) P-value = 0.000078

c) Lower bound = 0.0556

d) Upper bound = 0.1644

Step-by-step explanation:

This is a hypothesis test for the difference between proportions.

The claim is that the accident proportions differ between the two age groups .

Then, the null and alternative hypothesis are:

$H_0: \pi_1-\pi_2=0\\\\H_a:\pi_1-\pi_2\neq 0$

The significance level is 0.05.

The sample 1, of size n1=500 has a proportion of p1=0.36.

$p_1=X_1/n_1=180/500=0.36$

The sample 2, of size n2=600 has a proportion of p2=0.25.

$p_1=X_1/n_1=150/600=0.25$ .

The difference between proportions is (p1-p2)=0.11.

$p_d=p_1-p_2=0.36-0.25=0.11$

The pooled proportion, needed to calculate the standard error, is:

$p=\dfrac{X_1+X_2}{n_1+n_2}=\dfrac{180+150}{500+600}=\dfrac{330}{1100}=0.3$

The standard error for the difference between proportions can now be calculated as:

The estimated standard error of the difference between means is computed using the formula:

$s_{p1-p2}=\sqrt{\dfrac{p(1-p)}{n_1}+\dfrac{p(1-p)}{n_2}}=\sqrt{\dfrac{0.3*0.7}{500}+\dfrac{0.3*0.7}{600}}\\\\\\s_{p1-p2}=\sqrt{0.00042+0.00035}=\sqrt{0.00077}=0.0277$

Then, we can calculate the z-statistic as:

$z=\dfrac{p_d-(\pi_1-\pi_2)}{s_{p1-p2}}=\dfrac{0.11-0}{0.0277}=\dfrac{0.11}{0.0277}=3.964$

This test is a two-tailed test, so the P-value for this test is calculated as (using a z-table):

$P-value=2\cdot P(t>3.964)=0.000078$

As the P-value (0.000078) is smaller than the significance level (0.05), the effect is significant.

The null hypothesis is rejected.

There is enough evidence to support the claim that the accident proportions differ between the two age groups.

If we want to calculate the bounds of a 95% confidence interval, we start by calculating the margin of error.

For a 95% CI, the critical value for z is z=1.96.

Then, the margin of error is:

$MOE=z \cdot s_{p1-p2}=1.96\cdot 0.0277=0.0544$

Then, the lower and upper bounds of the confidence interval are:

$LL=(p_1-p_2)-z\cdot s_{p1-p2} = 0.11-0.0544=0.05561\\\\UL=(p_1-p_2)+z\cdot s_{p1-p2}= 0.11+0.0544=0.16439$

The 95% confidence interval for the population mean is (0.0556, 0.1644).

5 0

3 years ago

Evaluate the expression. (132−122)÷5 The value of the expression___ is