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3 years ago

Geometry help !! Please

Mathematics

2 answers:

attashe74 [19]3 years ago

8 0

A = 1/2bh = 1/2(23)(7) = 80.5

answer
D. 80.5

valentinak56 [21]3 years ago

5 0

area = 1/2 base x height

1/2 x 23 x7 = 80.5

answer is D 80.5

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Choose the correct graph of the given system of equations.<br><br> y − 2x = −1<br> x + 3y = 4

Slav-nsk [51]

I believe it'd the one in the middle because if you plug in the values (1,1) both equations are true.
Plug x=1 and y=1 in equations:
LHS = 1 - 2*1 = 1-2 = -1 = RHS
LHS = 1 + 3*1 = 4 = RHS
So it's the graph in the middle.

3 0

3 years ago

Read 2 more answers

Work out 1/2×7 write your answer mixed

Virty [35]

Answer:

1/2 x 7= 3.5

Step-by-step explanation:

6 0

3 years ago

Let A = −2 2 1 −3 1 1 2 0 −1 and B = 2 −1 0 1 2 1 −1 −2 4 . Use the matrix-column representation of the product to write each co

BigorU [14]

Answer:

AB = $\left[\begin{array}{ccc}-3&4&6\\-6&3&5\\5&0&-4\end{array}\right]$

Each column of AB is written as a linear combination of columns of Matrix A in the explanation below.

Step-by-step explanation:

A = $\left[\begin{array}{ccc}-2&2&1\\-3&1&1\\2&0&-1\end{array}\right]$

B= $\left[\begin{array}{ccc}2&-1&0\\1&2&1\\-1&-2&4\end{array}\right]$

We need to write each column of AB as a linear combination of the columns of A so we will multiply each column of A with each column element of B to get the column of AB. So,

AB Column 1 = 2 * $\left[\begin{array}{ccc}-2\\-3\\2\end{array}\right]$ + 1 $\left[\begin{array}{ccc}2\\1\\0\end{array}\right]$ + (-1) $\left[\begin{array}{ccc}1\\1\\-1\end{array}\right]$ = $\left[\begin{array}{ccc}-3\\-6\\5\end{array}\right]$

AB Column 2 = (-1) $\left[\begin{array}{ccc}-2\\-3\\2\end{array}\right]$ + 2 $\left[\begin{array}{ccc}2\\1\\0\end{array}\right]$ + (-2) $\left[\begin{array}{ccc}1\\1\\-1\end{array}\right]$ = $\left[\begin{array}{ccc}4\\3\\0\end{array}\right]$

AB Column 3 = (0) $\left[\begin{array}{ccc}-2\\-3\\2\end{array}\right]$ + (1) $\left[\begin{array}{ccc}2\\1\\0\end{array}\right]$ + 4 $\left[\begin{array}{ccc}1\\1\\-1\end{array}\right]$ = $\left[\begin{array}{ccc}6\\5\\-4\end{array}\right]$

Finally, we can combine all three columns of AB to form the 3x3 matrix AB.

AB = $\left[\begin{array}{ccc}-3&4&6\\-6&3&5\\5&0&-4\end{array}\right]$

4 0

3 years ago

Work out the shaded area

Dennis_Churaev [7]

Answer:

Step-by-step explanation:

Shaded area:

Area of big rectangle - Area of small rectangle

$= 10 \times 12 - (10 - 5) \times (12 - 2)$

Calculate the difference

$= 10 \times 12 - 5 \times 10$

Calculate the product

$= 120 - 50$

Calculate the difference

$= 70 \: {cm}^{2}$

Hope this helps...

Best regards!!

7 0

3 years ago

Find the number of elements in A 1 ∪ A 2 ∪ A 3 if there are 200 elements in A 1 , 1000 in A 2 , and 5, 000 in A 3 if (a) A 1 ⊆ A

lina2011 [118]

Answer:

a. 4600

b. 6200

c. 6193

Step-by-step explanation:

Let $n(A)$ the number of elements in A.

Remember, the number of elements in $A_1 \cup A_2 \cup A_3$ satisfies

$n(A_1 \cup A_2 \cup A_3)=n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)$

Then,

a) If $A_1\subseteq A_2, n(A_1 \cap A_2)=n(A_1)=200$ , and if $A_2\subseteq A_3, n(A_2\cap A_3)=n(A_2)=1000$

Since $A_1\subseteq A_2\; and \; A_2\subseteq A_3, \; then \; A_1\cap A_2 \cap A_3= A_1$

$n(A_1 \cup A_2 \cup A_3)=\\=n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)=\\=200+1000+5000-200-200-1000-200=4600$

b) Since the sets are pairwise disjoint

$n(A_1 \cup A_2 \cup A_3)=\\n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)=\\200+1000+5000-0-0-0-0=6200$

c) Since there are two elements in common to each pair of sets and one element in all three sets, then

$n(A_1 \cup A_2 \cup A_3)=\\=n(A_1)+n(A_2)+n(A_3)-n(A_1\cap A_2)-n(A_1\cap A_3)-n(A_2\cap A_3)-n(A_1\cap A_2 \cap A_3)=\\=200+1000+5000-2-2-2-1=6193$

8 0

3 years ago