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2 years ago

A^2+12a-7-3a^2-5a+8 what answer

Mathematics

2 answers:

Vitek1552 [10]2 years ago

6 0

Answer:

Step-by-step explanation:

a^2 + 12a - 7 - 3a^2 - 5a + 8

-2a^2 + 7a + 1

Sindrei [870]2 years ago

5 0

Ur answer is: -2a² + 7a + 1

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Please help and hurry please

kakasveta [241]

Answer:

x=7.48

Step-by-step explanation:

13^2+x^2=15^2

169+x^2=225

x^2=56

x=7.48

6 0

2 years ago

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Can I get the answer for the questions at the bottom

aniked [119]

27)

Equation of the existing water pipe's line

a) slope, m = rise / run = Δy / Δx = 3/2

b) y-intercept, b = 3

equation: y = mx + b = (3/2)x + 3

Equation of the new water pipe's line

slope, m = - 1 / (slope of the perpendicular line) = - 1 / (3/2) = - 2/3

point (0,2)

=> y - 2 = (-2/3) (x - 0) => y = (-2/3)x + 2 <---- equation of the new pipe

28)

two parallel lines have the same slope =>

slope, m = rise / run = Δy / Δx = [4 - 0] / [11 - 8] = 4 / 3

point (4,5) => y - 5 = (4/3) (x - 4)

=> y = (4/3)x - 16/3 + 5 = (4/3)x - 1/3

y = (4/3)x - 1/3 <--- equation of the new bike path

6 0

3 years ago

2.5% of a population are infected with a certain disease. There is a test for the disease, however the test is not completely ac

Aleks04 [339]

Answer:

$P(disease/positivetest) = 0.36116$

Step-by-step explanation:

This is a conditional probability exercise.

Let's name the events :

I : ''A person is infected''

NI : ''A person is not infected''

PT : ''The test is positive''

NT : ''The test is negative''

The conditional probability equation is :

Given two events A and B :

P(A/B) = P(A ∩ B) / P(B)

$P(B) >0$

P(A/B) is the probability of the event A given that the event B happened

P(A ∩ B) is the probability of the event (A ∩ B)

(A ∩ B) is the event where A and B happened at the same time

In the exercise :

$P(I)=0.025$

$P(NI)= 1-P(I)=1-0.025=0.975\\P(NI)=0.975$

$P(PT/I)=0.904\\P(PT/NI)=0.041$

We are looking for P(I/PT) :

P(I/PT)=P(I∩ PT)/ P(PT)

$P(PT/I)=0.904$

P(PT/I)=P(PT∩ I)/P(I)

0.904=P(PT∩ I)/0.025

P(PT∩ I)=0.904 x 0.025

P(PT∩ I) = 0.0226

P(PT/NI)=0.041

P(PT/NI)=P(PT∩ NI)/P(NI)

0.041=P(PT∩ NI)/0.975

P(PT∩ NI) = 0.041 x 0.975

P(PT∩ NI) = 0.039975

P(PT) = P(PT∩ I)+P(PT∩ NI)

P(PT)= 0.0226 + 0.039975

P(PT) = 0.062575

P(I/PT) = P(PT∩I)/P(PT)

$P(I/PT)=\frac{0.0226}{0.062575} \\P(I/PT)=0.36116$

8 0

2 years ago

Which one is smallest 0.28,1/4,15%,0.65,32%,1/3

sveticcg [70]

Answer:

15%

Step-by-step explanation:

8 0

2 years ago

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Use the following matrices, A, B, C and D to perform each operation.

Vinvika [58]

Step-by-step explanation:

$A=\left[\begin{array}{ccc}3&1\\5&7\end{array}\right]$

$B=\left[\begin{array}{ccc}4&1\\6&0\end{array}\right]$

$C=\left[\begin{array}{ccc}-2&3&1\\-1&0&4\end{array}\right]$

$D=\left[\begin{array}{ccc}-2&3&4\\0&-2&1\\3&4&-1\end{array}\right]$

$1.\\A+B=\left[\begin{array}{ccc}3&1\\5&7\end{array}\right]+\left[\begin{array}{ccc}4&1\\6&0\end{array}\right]=\left[\begin{array}{ccc}3+4&1+1\\5+6&7+0\end{array}\right]=\left[\begin{array}{ccc}7&2\\11&7\end{array}\right]$

$2.\\B-A=\left[\begin{array}{ccc}4&1\\6&0\end{array}\right]-\left[\begin{array}{ccc}3&1\\5&7\end{array}\right]=\left[\begin{array}{ccc}4-3&1-1\\6-5&0-7\end{array}\right]=\left[\begin{array}{ccc}1&0\\1&-7\end{array}\right]$

$3.\\3C=3\left[\begin{array}{ccc}-2&3&1\\-1&0&4\end{array}\right]=\left[\begin{array}{ccc}(3)(-2)&(3)(3)&(3)(1)\\(3)(-1)&(3)(0)&(3)(4)\end{array}\right]=\left[\begin{array}{ccc}-6&9&3\\-3&0&12\end{array}\right]$

$4.\\C\cdot D=\left[\begin{array}{ccc}-2&3&1\\-1&0&4\end{array}\right]\cdot\left[\begin{array}{ccc}-2&3&4\\0&-2&1\\3&4&-1\end{array}\right]\\\\=\left[\begin{array}{ccc}(-2)(-2)+(3)(0)+(1)(3)&(-2)(3)+(3)(-2)+(1)(4)&(-2)(4)+(3)(1)+(1)(-1)\\(-1)(-2)+(0)(0)+(4)(3)&(-1)(3)+(0)(-2)+(4)(4)&(-1)(4)+(0)(1)+(4)(-1)\end{array}\right]\\=\left[\begin{array}{ccc}7&-8&-6\\14&13&-8\end{array}\right]$

$5.\\2D+3C\\\text{This operation can't be performed because the matrices}\\\text{ are of different dimensions.}$

6 0

3 years ago