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3 years ago

I'm a bit confused. Can someone help?

Mathematics

1 answer:

cupoosta [38]3 years ago

5 0

Answer:

the answere is c

Step-by-step explanation:

it is easy and u should know this if u dont respond to me and i will help

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0.4.x -0.1=0.7 -0.3(6-2x)

cupoosta [38]

Answer:

x=5

Step-by-step explanation:

4 0

3 years ago

3 ft 9 in + 4 ft = <br> ft <br> in

Maurinko [17]

Answer:

7 ft and 9 inches

Step-by-step explanation:

6 0

2 years ago

Read 2 more answers

Please help and thank you so much in advanced

sdas [7]

x=18

y=-6

To find the x intercept, you would substitute the y with 0 and then solve for x.

To find the y intercept, you would substitute the x with 0 and solve for y.

Hope this helps braniliest please!

8 0

3 years ago

Read 2 more answers

Use Cramer Rule to solve the following system: 8x−5y=70 and 9x+7y=3

nlexa [21]

Answer:

$(x,y) = (5,-6)$

Step-by-step explanation:

$\underline{\textbf{Determinant of a matrix.}}\\\\\text{For a}~ 2 \times 2 ~ \text{matrix,}\\\\\begin{vmatrix} a_1&a_2\\b_1&b_2 \end{vmatrix} = a_1b_2 - a_2b_1\\\\\\\text{For a}~ 3 \times 3 ~ \text{matrix,}\\\\\begin{vmatrix} a_1&a_2&a_3\\ b_1&b_2&b_3\\ c_1&c_2&c_3 \end{vmatrix} = a_1\begin{vmatrix} b_2&b_3\\c_2&c_3 \end{vmatrix} - a_2 \begin{vmatrix} b_1&b_3\\c_1&c_3 \end{vmatrix}+ a_3 \begin{vmatrix} b_1&b_2\\c_1&c_2 \end{vmatrix}\\\\\\$

$~~~~~~~~~~~~~~~~~~=a_1(b_2c_3-b_3c_2) -a_2(b_1c_3-b_3c_1) +a_3(b_1c_2-b_2c_1)$

$\underline{\textbf{Cramer's Rule to solve a system of two equations.}}\\\\\text{Consider the system of two equations:}\\\\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~a_1x + b_1 y= c_1\\\\~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~a_2x +b_2 y = c_2\\\\\text{Here,}\\\\x = \dfrac{D_x}{D}= \dfrac{\begin{vmatrix} c_1&b_1\\c_2&b_2 \end{vmatrix}}{\begin{vmatrix} a_1&b_1\\a_2&b_2 \end{vmatrix}}\\\\\\ y= \dfrac{D_y}{D}= \dfrac{\begin{vmatrix} a_1&c_1\\a_2&c_2 \end{vmatrix}}{\begin{vmatrix} a_1&b_1\\a_2&b_2 \end{vmatrix}}\\\\$

$\underline{\textbf{Solution:}}\\\\~~~~~~~~~~~~~~~~~~~~~~~8x-5y = 70~~~~~~...(i)\\\\~~~~~~~~~~~~~~~~~~~~~~~9x +7y = 3~~~~~~~...(ii)\\\\\text{Applying Cramer's rule:}\\\\x = \dfrac{D_x}{D}\\\\\\~~=\dfrac{\begin{vmatrix} 70& -5 \\3&7 \end{vmatrix}}{\begin{vmatrix} 8& -5\\ 9& 7\end{vmatrix}}\\\\\\~~=\dfrac{70(7) -(-5)(3)}{(8)(7)-(-5)(9)}\\\\\\~~=\dfrac{490+15}{56+45}\\\\\\~~=\dfrac{505}{101}\\\\\\~~=5$

$y = \dfrac{D_y}{D}\\\\\\~~=\dfrac{\begin{vmatrix} 8& 70 \\9&3 \end{vmatrix}}{\begin{vmatrix} 8& -5\\ 9& 7\end{vmatrix}}\\\\\\~~=\dfrac{(8)(3) -(70)(9)}{(8)(7)-(-5)(9)}\\\\\\~~=\dfrac{24-630}{56+45}\\\\\\~~=-\dfrac{606}{101}\\\\\\~~=-6$

$\textbf{Hence, the solution to the system of equation is}~ (x,y) = (5,-6)$

7 0

2 years ago

10# A consumer advocacy group is doing a large study on car rental practices. Among other things, the consumer group would like

ella [17]

ANSWER:

104

STEP-BY-STEP EXPLANATION:

Given:

Standard deviation (σ) = 700

Confidence level = 95%

Mean error (Eμ) = 135

We have for a confidence level of 95%:

$\begin{gathered} \alpha=100\%-95\%=5\%=0.05 \\ \\ \alpha\text{/2}=\frac{0.05}{2}=0.025 \\ \\ \text{ The corresponding Z value for \alpha/2 = 0.025 is as follows:} \\ \\ Z_{\alpha\text{/2}}=1.96 \end{gathered}$

Now, we calculate the minimum value of the sample size as follows:

$\begin{gathered} n=\left(\frac{Z_{\alpha\text{/2}}\cdot\sigma}{E}\right)^2 \\ \\ \text{ We replacing:} \\ \\ \:n=\left(\frac{1.96\cdot 700}{135}\right)^2 \\ \\ \:n=103.2858\cong104 \end{gathered}$

The minimum sample size needed is 104

3 0

1 year ago