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3 years ago

SIMPLIFY the expression

Mathematics

2 answers:

strojnjashka [21]3 years ago

6 0

7, 7x7 is of course 49

Burka [1]3 years ago

4 0

The answer to your question is 7

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Determine whether line AB and line CD are parallel, perpendicular, or neither. A( 4, 2), B(-3, 1), C(6, 0), D(-10, 8)

Lapatulllka [165]

Answer:

<h2>neither</h2>

Step-by-step explanation:

If AB an CD are parallel, then their slopes are the same.

If AB and CD are perpendicular, then the product of their slopes is equal -1.

The formula of a slope:

$m=\dfrac{y_2-y_1}{x_2-x_1}$

Calculate the both slope:

$A(4,\ 2),\ B(-3,\ 1)\\\\m_{AB}=\dfrac{1-2}{-3-4}=\dfrac{-1}{-7}=\dfrac{1}{7}\\\\C(6,\ 0),\ D(-10,\ 8)\\\\m_{CD}=\dfrac{8-0}{-10-6}=\dfrac{8}{-16}=-\dfrac{1}{2}\\\\=============================$

$m_{AB}\neq m_{CD}$

The line AB and line CD are not parallel

$m_{AB}\cdot m_{CD}=\left(\dfrac{1}{7}\right)\left(-\dfrac{1}{2}\right)=-\dfrac{1}{14}\neq-1$

The line AB and line CD are not perpendicular.

6 0

3 years ago

Two researchers conducted a study in which two groups of students were asked to answer 42 trivia questions from a board game. Th

Verizon [17]

Answer:

$(21.9-19.8) -1.966\sqrt{\frac{3.4^2}{200} +\frac{3.5^2}{200}}= 1.422$

$(21.9-19.8) -1.966 \sqrt{\frac{3.4^2}{200} +\frac{3.5^2}{200}}= 2.778$

And we are 95% confident that the true difference means are between $1.422 \leq \mu_1 -\mu_2 \leq 2.778$

Step-by-step explanation:

We know the following info:

$\bar X_1 = 21.9$ sample mean for group 1

$\bar X_2 = 19.8$ sample mean for group 2

$s_1 = 3.4$ sample standard deviation for group 1

$s_2 = 3.5$ sample standard deviation for group 2

$n_1 = 200$ sample size group 1

$n_2 = 200$ sample size group 2

We want to find a confidence interval for the difference of means and the correct formula to do this is:

$(\bar X_1 -\bar X_2) \pm t_{\alpha/2} \sqrt{\frac{s^2_1}{n_1} +\frac{s^2_2}{n_2}}$

Now we just need to find the critical value. The confidence level is 0.95 then the significance is $1-0.95 =0.05$ and $\alpha/2 =0.025$ . The degrees of freedom are given by: