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Feliz [49]
3 years ago
9

The ratio of boys to girls at a concert is 13:17. If there are a total of 90 children at the concert, how many boys are at the c

oncert?
Mathematics
1 answer:
Gwar [14]3 years ago
6 0
Their is 40 boys at the concert
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Need help please. I'm having trouble with this question and I need to get this right on my study guide for my big test to past.
Rufina [12.5K]
The ordered pair (1, 40) represents the unit rate of the relationship.
The ordered pair (3, 120) means that Tien can type 120 words in 3 minutes.
7 0
3 years ago
Part 1.] Does the graph have even symmetry, odd symmetry, or neither?
QveST [7]
Part 1
The graph has even symmetry.  You can see that because it is symmetric with respect to the y-axis.
Functions that have even symmetry have the following property:
f(x)=f(-x)
Part 2
To answer this we can simply check if the property we mentioned earlier holds for this function.
sin(\frac{\pi}{2})\ne sin(-\frac{\pi}{2})
We can see that sine does not have even symmetry. 
In fact, sine function has the following property: 
sin(x)=-sin(x)
This is called odd symetry.
Part 3
Take a look at the function that you attached in the picture. We know that function has even symmetry. 
Reflection over x-axis and <span>180° rotation around the origin would give us -f(x). We would not end up with the same function, so these two are out. 
</span><span>90° rotation around the origin would mean we swapped x <span>and y</span> so that one is out too. R</span><span>eflection over the line y=x is a property of functions that have an odd symmetry.
We are left with reflection around y-axis and, as mentioned before, this is the property of evenly symmetric functions.</span>
4 0
3 years ago
An irrational number between 5 and 7
zhenek [66]
One irrational number between 5 and 7 is \sqrt{37}.
7 0
3 years ago
Solve for XX. Assume XX is a 2×22×2 matrix and II denotes the 2×22×2 identity matrix. Do not use decimal numbers in your answer.
sveticcg [70]

The question is incomplete. The complete question is as follows:

Solve for X. Assume X is a 2x2 matrix and I denotes the 2x2 identity matrix. Do not use decimal numbers in your answer. If there are fractions, leave them unevaluated.

\left[\begin{array}{cc}2&8\\-6&-9\end{array}\right]· X·\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right] =<em>I</em>.

First, we have to identify the matrix <em>I. </em>As it was said, the matrix is the identiy matrix, which means

<em>I</em> = \left[\begin{array}{ccc}1&0\\0&1\end{array}\right]

So, \left[\begin{array}{cc}2&8\\-6&-9\end{array}\right]· X·\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right] =  \left[\begin{array}{ccc}1&0\\0&1\end{array}\right]

Isolating the X, we have

X·\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]= \left[\begin{array}{cc}2&8\\-6&-9\end{array}\right] -  \left[\begin{array}{ccc}1&0\\0&1\end{array}\right]

Resolving:

X·\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]= \left[\begin{array}{ccc}2-1&8-0\\-6-0&-9-1\end{array}\right]

X·\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]=\left[\begin{array}{ccc}1&8\\-6&-10\end{array}\right]

Now, we have a problem similar to A.X=B. To solve it and because we don't divide matrices, we do X=A⁻¹·B. In this case,

X=\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]⁻¹·\left[\begin{array}{ccc}1&8\\-6&-10\end{array}\right]

Now, a matrix with index -1 is called Inverse Matrix and is calculated as: A . A⁻¹ = I.

So,

\left[\begin{array}{ccc}9&-3\\7&-6\end{array}\right]·\left[\begin{array}{ccc}a&b\\c&d\end{array}\right]=\left[\begin{array}{ccc}1&0\\0&1\end{array}\right]

9a - 3b = 1

7a - 6b = 0

9c - 3d = 0

7c - 6d = 1

Resolving these equations, we have a=\frac{2}{11}; b=\frac{7}{33}; c=\frac{-1}{11} and d=\frac{-3}{11}. Substituting:

X= \left[\begin{array}{ccc}\frac{2}{11} &\frac{-1}{11} \\\frac{7}{33}&\frac{-3}{11}  \end{array}\right]·\left[\begin{array}{ccc}1&8\\-6&-10\end{array}\right]

Multiplying the matrices, we have

X=\left[\begin{array}{ccc}\frac{8}{11} &\frac{26}{11} \\\frac{39}{11}&\frac{198}{11}  \end{array}\right]

6 0
3 years ago
A company makes a block of cheese in the shape of a rectangular prism with dimensions 4 inches by 2 inches by 2 inches. They wan
Art [367]

Answer:

Step-by-step explanation:

pyramid has a height of 5 inches and a volume of 60 cubic inches. Select all figures that could be the base for this pyramid.

A:

a square with side length 6 inches

B:

a 3 inch by 4 inch rectangle

C:

a 4 inch by 9 inch rectangle

D:

a circle with radius 4 inches

E:

a right triangle with one side 5 inches and the hypotenuse 13 inches

F:

a hexagon with an area of 36 square inches

8 0
3 years ago
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