Help me please !!!!

Simplify.<br><br> 22÷(9+2) Need help

Vilka [71]

22 / (9 + 2) =
22 / 11 =
2 <==

7 0

4 years ago

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Factor completely x3 − 2x2 − 5x + 10.

Akimi4 [234]

Answer:

(x-2) (x^2 -5)

Step-by-step explanation:

x^3 − 2x^2 − 5x + 10

We will factor by grouping

Take and x^2 out of the first two terms and -5 out of the last two terms

x^2 (x-2) -5(x-2)

Now we can factor out (x-2)

(x-2) (x^2 -5)

5 0

3 years ago

A scuba diver is 3.8 meters below the surface of the water. He is descending at a rate of 0.5 meters per minute.

Andreyy89

-3.8 - 0.5m <== ur expression

the variable (m) represents number of minutes

5 0

3 years ago

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5) In a certain supermarket, a sample of 60 customers who used a self-service checkout lane averaged 5.2 minutes of checkout tim

Ne4ueva [31]

Answer:

$\S^2_p =\frac{(60-1)(3.1)^2 +(72 -1)(2.8)^2}{60 +72 -2}=8.643$

$S_p=2.940$

$t=\frac{(5.2 -6.1)-(0)}{2.940\sqrt{\frac{1}{60}+\frac{1}{72}}}=-1.751$

$df=60+72-2=130$

$p_v =P(t_{130}$

Assuming a significance level of $\alpha=0.05$ we have that the p value is lower than this significance level so then we can conclude that the mean for checkout time is significantly less for people who use the self-service lane

Step-by-step explanation:

Data given

Our notation on this case :

$n_1 =60$ represent the sample size for people who used a self service

$n_2 =72$ represent the sample size for people who used a cashier

$\bar X_1 =5.2$ represent the sample mean for people who used a self service

$\bar X_2 =6.1$ represent the sample mean people who used a cashier

$s_1=3.1$ represent the sample standard deviation for people who used a self service

$s_2=2.8$ represent the sample standard deviation for people who used a cashier

Assumptions

When we have two independent samples from two normal distributions with equal variances we are assuming that

$\sigma^2_1 =\sigma^2_2 =\sigma^2$

The statistic is given by:

$t=\frac{(\bar X_1 -\bar X_2)-(\mu_{1}-\mu_2)}{S_p\sqrt{\frac{1}{n_1}+\frac{1}{n_2}}}$

And t follows a t distribution with $n_1+n_2 -2$ degrees of freedom and the pooled variance $S^2_p$ is given by this formula:

$\S^2_p =\frac{(n_1-1)S^2_1 +(n_2 -1)S^2_2}{n_1 +n_2 -2}$

System of hypothesis

Null hypothesis: $\mu_1 \geq \mu_2$

Alternative hypothesis: $\mu_1 < \mu_2$

This system is equivalent to:

Null hypothesis: $\mu_1 - \mu_2 \geq 0$

Alternative hypothesis: $\mu_1 -\mu_2 < 0$

We can find the pooled variance:

$\S^2_p =\frac{(60-1)(3.1)^2 +(72 -1)(2.8)^2}{60 +72 -2}=8.643$

And the deviation would be just the square root of the variance:

$S_p=2.940$

The statistic is given by:

$t=\frac{(5.2 -6.1)-(0)}{2.940\sqrt{\frac{1}{60}+\frac{1}{72}}}=-1.751$

The degrees of freedom are given by:

$df=60+72-2=130$

And now we can calculate the p value with:

$p_v =P(t_{130}$

Assuming a significance level of $\alpha=0.05$ we have that the p value is lower than this significance level so then we can conclude that the mean for checkout time is significantly less for people who use the self-service lane

5 0

3 years ago

Find the GCF. 14abc and 28a2b2c3

Zarrin [17]

The greatest common factor is the largest factor that both terms share.

First, start with the coefficients, 14 and 28. The largest factor they both share is 14. 14 x 1 = 14, 14 x 2 = 28.

Next we move to the variables, abc and a²b²c³. The largest factor the both share is abc, all to the power of 1.

So, your GCF and final answer is 14abc

5 0

3 years ago