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2 years ago

Hello people ~factorise↷ x^2 + 4x –21

Mathematics

1 answer:

EleoNora [17]2 years ago

8 0

Let's see

$\\ \rm\rightarrowtail x^2+4x-21$

$\\ \rm\rightarrowtail x^2+7x-3x-21$

$\\ \rm\rightarrowtail x(x+7)-3(x+7)$

$\\ \rm\rightarrowtail (x-3)(x+7)$

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Solve the inequality graph and check the solution. 5>z-3

AnnZ [28]

Answer:

z < 8

Step-by-step explanation:

Add 3 to both sides

8 > z OR z < 8

7 0

2 years ago

The volume of a sphere is 32 3 π cubic centimeters. What is the radius? Sphere V = 4 3 πr3

allsm [11]

Answer:

To solve for the volume of a sphere, you must first know the equation for the volume of a sphere.

V=43(π)(r3)

In this equation, r is equal to the radius. We can plug the given radius from the question into the equation for r.

V=43(π)(123)

Now we simply solve for V.

V=43(π)(1728)

V=(π)(2304)=2304π

Answer is 2304

4 0

2 years ago

Read 2 more answers

(5x3 + 3)2 = (5x3)2 + (3)2 = 25x6 + 9 Determine if Louise’s answer is correct. Explain.

MrMuchimi

Louise’s answer is not correct. She is missing the term 30x3. When squaring a binomial, it is best to write the product of the binomial times itself. Then you can use the distributive property to multiply each term in the first binomial by each term in the second binomial. Louise also could have used the formula for a perfect square trinomial, which is found by squaring a binomial.

3 0

2 years ago

What is 249 rounded to the nearest ten

Vinil7 [7]

That would be 250 if rounded to the nearest ten.

6 0

3 years ago

Location is known to affect the number, of a particular item, sold by an automobile dealer. Two different locations, A and B, ar

yKpoI14uk [10]

Answer:

We conclude that the true mean number of sales at location A is fewer than the true mean number of sales at location B.

Step-by-step explanation:

We are given that Location A was observed for 18 days and location B was observed for 13 days.

On average, location A sold 39 of these items with a sample standard deviation of 8 and location B sold 49 of these items with a sample standard deviation of 4.

Let $\mu_1$ = true mean number of sales at location A.

$\mu_2$ = true mean number of sales at location B

So, Null Hypothesis, $H_0$ : $\mu_1-\mu_2\geq0$ or $\mu_1 \geq \mu_2$ {means that the true mean number of sales at location A is greater than or equal to the true mean number of sales at location B}

Alternate Hypothesis, $H_A$ : $\mu_1-\mu_2$ or $\mu_1< \mu_2$ {means that the true mean number of sales at location A is fewer than the true mean number of sales at location B}

The test statistics that would be used here Two-sample t test statistics as we don't know about the population standard deviations;

T.S. = $\frac{(\bar X_1-\bar X_2)-(\mu_1-\mu_2)}{s_p\sqrt{\frac{1}{n_1}+\frac{1}{n_2} } }$ ~ $t_n__1_-_n__2-2$

where, $\bar X_1$ = sample average of items sold at location A = 39

$\bar X_2$ = sample average of items sold at location B = 49

$s_1$ = sample standard deviation of items sold at location A = 8

$s_2$ = sample standard deviation of items sold at location B = 4

$n_1$ = sample of days location A was observed = 18

$n_2$ = sample of days location B was observed = 13

Also, $s_p=\sqrt{\frac{(n_1-1)s_1^{2}+(n_2-1)s_2^{2} }{n_1+n_2-2} }$ = $\sqrt{\frac{(18-1)\times 8^{2}+(13-1)\times 4^{2} }{18+13-2} }$ = 6.64

So, test statistics = $\frac{(39-49)-(0)}{6.64 \times \sqrt{\frac{1}{18}+\frac{1}{13} } }$ ~ $t_2_9$

= -4.14

The value of t test statistics is -4.14.

Now, at 0.01 significance level the t table gives critical value of -2.462 at 29 degree of freedom for left-tailed test.

Since our test statistics is less than the critical values of t as -2.462 > -4.14, so we have sufficient evidence to reject our null hypothesis as it will fall in the rejection region due to which we reject our null hypothesis.

Therefore, we conclude that the true mean number of sales at location A is fewer than the true mean number of sales at location B.

3 0

2 years ago

Hello people ~factorise↷ x^2 + 4x –21​

Hello people ~factorise↷ x^2 + 4x –21