Which trinomial is the product of the expression below? (2r-5)(r+10

Oof I am really confused on 13. Can someone help me with it? I’ll really appreciate it. Thanks!

Nataly [62]

Hi! I know for sure that a and d are equivalent to the expression which is not what you are looking for. This is because 11 times 8 gives you the 88 on a and if you multiply the 5 also by 8 you get 40 so a is not the answer. The reason I multiply both by the same number and got the equivalency is because, "What you do to one side, you do to the other." Same thing with d. My answer would be B because you can't change the variable to a different number. You can't just give the five the y and make it mean the same. The answer is B.

3 0

3 years ago

Simplify 5(a - b. 6(a b. - 7(a - 2b)

Elan Coil [88]

Not sure what you're asking. are you wanting to solve 5 ( a - b), where b equals those two things listed below? If that's the case, I can definitely help. If not, please clarify.

6 0

3 years ago

A researcher finds that of 1000 people who said that they attend a religious service at least once a week, A stopped to help a p

Ne4ueva [31]

Answer:

There is enough evidence to support the claim that the proportions are not equal. (P-value: 0.048).

Step-by-step explanation:

The question is incomplete:

"A researcher finds that of 1000 people who said that they attend a religious service at least once a week, 31 stopped to help a person with car trouble. Of 1200 people interviewed who had not attended a religious service at least once a month, 22 stopped to help a person with car trouble. At the 0.05 significance level, test the claim that the two proportions are different."

This is a hypothesis test for the difference between proportions.

The claim is that the proportions are not equal.

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=1000 has a proportion of p1=0.031.

$p_1=X_1/n_1=31/1000=0.031$

The sample 2, of size n2=1200 has a proportion of p2=0.018.

$p_2=X_2/n_2=22/1200=0.018$

The difference between proportions is (p1-p2)=0.013.

$p_d=p_1-p_2=0.031-0.018=0.013$

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

$p=\dfrac{X_1+X_2}{n_1+n_2}=\dfrac{31+22}{1000+1200}=\dfrac{53}{2200}=0.024$

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

$s_{p1-p2}=\sqrt{\dfrac{p(1-p)}{n_1}+\dfrac{p(1-p)}{n_2}}=\sqrt{\dfrac{0.024*0.976}{1000}+\dfrac{0.024*0.976}{1200}}\\\\\\s_{p1-p2}=\sqrt{0+0}=\sqrt{0}=0.007$

Then, we can calculate the z-statistic as:

$z=\dfrac{p_d-(\pi_1-\pi_2)}{s_{p1-p2}}=\dfrac{0.013-0}{0.007}=\dfrac{0.013}{0.007}=1.98$

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

$P-value=2\cdot P(z>1.98)=0.048$

As the P-value (0.048) 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 proportions are not equal.

6 0

3 years ago

Plz help I am very confused on this

user100 [1]

Answer:

(-4, 0)

Step-by-step explanation:

(-4, 0)

8 0

3 years ago

The proper angle for a ladder is about 75 ∘ 75∘ from the ground. suppose you have a 14 foot ladder. how far from the house shoul

jonny [76]

We just use the sinus rule to calculate this

a / sin alpha = b / sin beta

Alpha is the 90 degree angle from the wall to the floor
beta is the angle from the top of the ladder to the wall,
wich is 90 degrees - 75 degrees (triangle has 180 degrees angles, one is 90 degrees), so beta = 15 degrees

14 foot / sin 90 = b / sin 15
sin 90 = 1
we move the sin15 over to the other side

14 foot x sin 15 = b
b = 3.62 foot

5 0

3 years ago