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3 years ago

-4(5x)=12 is it true false or open?

Mathematics

2 answers:

Ipatiy [6.2K]3 years ago

8 0

False if that's what you're asking

icang [17]3 years ago

7 0

Answer:

True when x = -3/5; false otherwise

Step-by-step explanation:

Note that -4(5x) = 12 => -20x = 12, so that x = -3/5. The given equation is solveable, and the solution is -3/5. Asking whether -4(5x)=12 is "true" or "false" is pointless; this equation is conditionally true, with that truth hinging on x = -3/5. Similarly, -4(5x)=12 is not describable by "open."

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sally walks 4 miles north and then 3 miles east. how far has she walked as the crow flies from her starting point?

wolverine [178]

Answer:

Step-by-step explanation:

Use Pythagorean’s theorem

Find the hypotenuse

16 + 9 = c squared

25 = c squared

5 = c

8 0

3 years ago

In a study of 24 criminals convicted of antitrust offenses, the average age was 60 years, with a standard deviation of 7.4 years

Alexxandr [17]

Answer: 56.9 years to 63.1 years.

Step-by-step explanation:

Confidence interval for population mean (when population standard deviation is unknown):

$\overline{x}\pm t_{\alpha/2}{\dfrac{s}{\sqrt{n}}}$

, where $\overline{x}$ = sample mean, n= sample size, s= sample standard deviation, $t_{\alpha/2}$ = Two tailed t-value for $\alpha$ .

Given: n= 24

degree of freedom = n- 1= 23

$\overline{x}$ = 60 years

s= 7.4 years

$\alpha=0.05$

Two tailed t-critical value for significance level of $\alpha=0.05$ and degree of freedom 23:

$t_{\alpha/2}=2.0687$

A 95% confidence interval on the true mean age:

$60\pm (2.0686){\dfrac{7.4}{\sqrt{24}}}\\\\\approx60\pm3.1\\\\=(60-3.1,\ 60+3.1)\\\\=(56.9,\ 63.1)$

Hence, a 95% confidence interval on the true mean age. : 56.9 years to 63.1 years.

5 0

4 years ago

can anyone help me??? A bakery sells muffins for $3.50 each. A beverage is $1.75. A class purchases 32 items and spends a total

inna [77]

Answer:

(a) $\begin{bmatrix} 1 &1 \\ 2 & 1\end{bmatrix}\cdot\begin{bmatrix}x\\ y\end{bmatrix}=\begin{bmatrix}32\\ 50\end{bmatrix}$

(b) determinant of the matrix is: -1

(c) number of muffins purchased=18

number of beverages purchased=14.

Step-by-step explanation:

(a) let us assume that the number of muffins purchased=x

number of beverage purchased=y

as a class purchased a total of 32 items that means x+y=32

amount spent=$87.50 that means 3.50x+1.75y=87.50

which could also be written as: 2x+y=50

now in matrix form it could be represented as:

$\begin{bmatrix} 1 &1 \\ 2 & 1\end{bmatrix}\cdot\begin{bmatrix}x\\ y\end{bmatrix}=\begin{bmatrix}32\\ 50\end{bmatrix}$

(b) the determinant of the matrix $\begin{bmatrix} 1 &1 \\ 2 & 1\end{bmatrix}$ is given by $1\times1-2\times1=1-2=-1$

hence the determinant of the matrix is: -1

(c) now on solving the matrix we need to apply row operations in it to make it a upper triangular matrix so that it would be easy for us to calculate the value of x and y.

$\begin{bmatrix} 1 &1 \\ 2 & 1\end{bmatrix}\cdot\begin{bmatrix}x\\ y\end{bmatrix}=\begin{bmatrix}32\\ 50\end{bmatrix}$

we multiply row 1 by 2 and subtract row 2 from it to get

$\begin{bmatrix} 1 &1 \\ 0 & 1\end{bmatrix}\cdot\begin{bmatrix}x\\ y\end{bmatrix}=\begin{bmatrix}32\\ 14\end{bmatrix}$

on using the backward substitution in the matrix we get y=14

and x=18

Hence, number of muffins purchased=18

number of beverages purchased=14.

5 0

3 years ago

Read 2 more answers

Solve this trinomial Z^2 + z = -20

Naddik [55]

Answer:

your answer is a complex number making your question wrong

Step-by-step explanation:

First z²+z+20=0, just to make it a quadratic equation, so we can use the quadratric formula:

x=( -b±√b²-4ac)/2a

so to find a b and c we compare

YOUR QUESTION SHOULD BE Z² +Z-20=O.

4 0

3 years ago

Find the measure of the missing angle in the quadrilateral

photoshop1234 [79]

Answer:

11) x=80

12) x=40

13) x=8

6 0

4 years ago