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Schach [20]
2 years ago
7

Please help me with this.

Mathematics
1 answer:
OLga [1]2 years ago
8 0

Swapping rows alters the sign of the determinant:

\begin{vmatrix} x & y & z \\ -8 & 2 & -12 \\ u & v & w \end{vmatrix} = - \begin{vmatrix} x & y & z \\ u & v & w \\ -8 & 2 & -12 \end{vmatrix}

Multiplying a single row by a scalar scales the determinant by the same amount:

\begin{vmatrix} x & y & z \\ u & v & w \\ -8 & 2 & -12 \end{vmatrix} = -2 \begin{vmatrix} x & y & z \\ u & v & w \\ 4 & -1 & 6 \end{vmatrix}

Then

\begin{vmatrix} x & y & z \\ -8 & 2 & -12 \\ u & v & w \end{vmatrix} = -(-2) \begin{vmatrix} x & y & z \\ u & v & w \\ 4 & -1 & 6 \end{vmatrix} = 2\times(-6) = \boxed{-12}

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What is the surface area of the figure shown? (use 3.14 for pi)
SpyIntel [72]

This is a combination of the formula of several figures.

The first one is the bottom of the cylinder AKA a circle.
The second one is the cylinder - the bottom and the top.
The third one is a cone without a bottom.

The first one can be written like this: r^2*3.14 where r is the radius of the circle
The second one is written like this: 2*3.14*r*h where r is the radius, and h the height
The third one is written like this: l*r*3.14

After this you just have to input the values. 
bottom        cylinder        Cone             (Use calculator if possible)
(3^2*3.14)+(2*3.14*3*5)+(6*3*3.14)=
28.26 + 94.2 + 56.52 = 178.98 in^2

The correct answer is 178.98 in^2.
Youre welcome. 




EXTRA:

If youre wondering how to find the different formulas, you can search for the full formula, then remove the parts you do not need, by matching them with the formula of the part you want to remove.

Example:
Cylinder:
SA = 2(pi<span> r</span><span> 2</span><span>) + (2 </span><span>pi </span><span>r)* h
</span>In this case, i didnt need the top and bottom, then i look for the formula of a circle.
Circle SA = pi r^2

Is this anywhere in the cylinder? Yes! The first part.
Then we are left with:
2 + (2 pi r)*h
But that 2 looks strangely placed, and with some reason, one quickly understands that it means "top AND bottom", but since we removed the circle surface, we have to remove that part too. 
So the final result of the formula is:
2 pi r h


4 0
4 years ago
A 40 meter ladder makes an angle of 32° with the playground. How far is the bottom of the ladder from the base of the playground
postnew [5]

Answer:

33.9 m

Step-by-step explanation:

cos(32) = adjacent/hypotenuse

cos(32) = X/40

X = 40cos(32)

X = 33.92192385 m

4 0
3 years ago
The first day of Sam's vacation was a Monday. What day of the week was the Day 36 of Sam's vacation?
makvit [3.9K]

Answer:

A. Monday

Step-by-step explanation:

The solution to this problem can be found by creating a table

If Day 1 was Monday, then

Mon    Tues      Wed      Thur    Fri      Sat      Sun

1              2           3             4        5        6          7

8             9           10           11        12       13        14

...............

We can see that the multiples of 7 are falling on Sundays so we will divide 36 by 7 to get the closest multiple of 7 to 36.

The closest multiple of 7 near 36 is 35 so Day 35th will fall on Sunday and Day 36 will be on Monday

Hence, Option A is the correct answer..

3 0
3 years ago
Lisa ate 1/8 of a pizza. Josh ate 21/2 times a much as Lisa. What fraction of the pizza did josh eat
Aliun [14]
Josh ate 5/2 of the pizza
3 0
3 years ago
Read 2 more answers
Find the Volume. Plz Help
koban [17]

Answer:

B

Step-by-step explanation:

V = \frac{l*w*h}{2} = \frac{18*12*9}{2} = \frac{1944}{2} = 972

3 0
3 years ago
Read 2 more answers
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