Առաջադրանքներ հեևյալ խնդրագրքից՝ 34-36,էջ 17

Վարժ․34

ա)

{ x+2y=3 | 0

{ x+y = -1 | 2

y= 3+(-1)=3+1=4

y=4

x+8=3

x= -5

(-5;4)

բ)

{ x=3y-3

{ 3y-3+y-1=0

4y=4

y=1

x=3-3=0

(0;1)

գ)

{ 4x+y-2=0

{ 3x+y+3=0

y= -4x+2

3x-4x+2+3=0

-x= -3-2= -5

x=5

y= -20+2= -18

(5;-18)

դ)

{ x-y-7=0

{ 3x-y+1=0

x=7+y

3(7+y)-y+1=0

21+3y-y+1=0

2y= -22

y= -22/2= -11

x=7-11= -4

(-4; -11)

Վարժ․35

ա)

+{ x+3y-1=0

+{ -x+4y+8=0

7y+7=0

7y= -7

y= -1

x+3*(-1)-1=0

x=1+3

x=4

(4:-1)

ստ․

4+(-3)-1=0

1-1=0

բ)

{ x-2y+3=0

+{ -x+3y+2=0

y+5=0

y=0-5

y= -5

x-2*(-10)+3=0

-2*(-5)=10

x+13=0

x=0-13

x= -13

գ)

{ x-y+2=0

{ 3x+y-4=0

x=y-2

3(y-2)+y-4=0

3y-6+y-4=0

4y=4+6=10

y=10/4=2.5

x=2.5-2=0.5

(0.5;2.5)

դ)

{ 2x+y-3=0

{ -x-y+4=0

y=3-2x

-x-(3-2x)+4=0

-x-3+2x+4=0

x= -3+4=1

x=1

y=3-2=1

(1;1)

Վարժ․ 36

ա)

{ x+2y-3=0

{ 2x-3y+8=0

-{ 2x+4y-6=0

-{ 2x-3y+8=0

7y-14=0

7y=0-14

7y= -14

y= -2

x+ (-2*2)-3=0

x+(-4)-3=0

x= -4-3

x= -7

(-7;-2)

բ)

{ 2x+y-8=0

{ 3x+4y-7=0

y=8-2x

3x+4(8-2x)-7=0

3x+32-8x-7=0

-5x=7-32

-5x -25

-x= -5

x=5

y=8-10= -2

(5; -2)

գ)

{ -6x+2y+6=0

{ 5x-y-17=0

y= -17+5x

-6x+2(-17+5x)+6=0

-6x-34+10x+6=0

4x=34-6=28

x=28/4=7

y= -17+35=18

(7;18)

դ)

{ 5x+3y-7=0

{ 2x-y-5=0

y=2x-5

5x+3(2x-5)-7=0

5x+6x-15-7=0

11x=7+15=22

x=22/11=2

y=4-5= -1

(2; -1)

ե)

{ 2x+5y-15=0

{ 3x+2y-6=0

3x+7.5y-22.5=0

3x+2y-6=0}

3x+7.5y-22.5-(3x+2y-6)=0

3x+7.5y-22.5-3x-2y+6=0

5.5y=22.5-6

5.5y=16.5

y=16.5/5.5=3

3x+22.5-22.5=0

3x= -22.5+22.5=0

x=0/3=0

(0;3)

զ)

{ 4x-5y-3=0

{ 3x-2y-11=0

{ 4x-5y-3=0

7,5x-5y-27,5=0

4x-5y-3-(7,5x-5y-27,5)=0

4x-5y-3-7,5x+5y+27,5=0

-3.5x= -27,5+3= -24,5

-x= -24,5/3,5= -7

x=7

52,5-5y-27,5=0

-5y=27,5-52,5= 25

-y=5

y= -5

(7; -5)

է)

{ 2x+4y-6=0

{ 3x-2y-25=0

{ 2x+4y-6=0

6x-4y-50=0}

2x+4y-6+6x-4y-50=0

8x=56

x=56/8=7

42-4y-50=0

-4y=50-42=8

-y=8/4=2

y= -2

(7; -2)

Albert Zaven Kapikian

Albert Zaven Kapikian (1930 – 2014) was an Armenian-American virologist who developed the first licensed vaccine against rotavirus, the most common cause of severe diarrhea in infants. He was awarded the Sabin Gold Medal for his pioneering work on the vaccine. He is the 13th recipient of this recognition, awarded annually by the Sabin Vaccine Institute. Called the father of human gastroenteritis virus research, Kapikian identified the first norovirus, initially called Norwalk virus, in 1972; and he and his colleagues at the National Institutes of Health identified the hepatitis A virus in 1973.

Kapikian graduated from Cornell Medical College in 1956 and began a career with the National Institutes of Health in 1957. In 1970 he spent six months in the UK where at the suggestion of his boss he studied the techniques of June Almeida. Almedia took the first photos of coronavirus using novel techniques. Back in the USA he used these techniques to identify non-bacterial gastroenteritis — Norwalk virus.

He was chief of the epidemiology section of the Laboratory of Infectious Diseases at NIH’s National Institute of Allergy and Infectious Diseases (NIAID), a position he held for 45 years. In 1998 he was appointed Deputy Director of the National Institute of Allergy and Infectious Diseases.

Kapikian died on February 24, 2014, at the age of 83.

Rotavirus vaccine

Rotavirus vaccine is a vaccine used to protect against rotavirus infections, which are the leading cause of severe diarrhea among young children. The vaccines prevent 15–34% of severe diarrhea in the developing world and 37–96% of severe diarrhea in the developed world. The vaccines decrease the risk of death among young children due to diarrhea. Immunizing babies decreases rates of disease among older people and those who have not been immunized.

The World Health Organization (WHO) recommends that rotavirus vaccine be included in national routine vaccinations programs, especially in areas where the disease is common. This should be done along with promoting breastfeeding, handwashing, clean water, and good sanitation. It is given by mouth and requires two or three doses. It should be given starting around six weeks of age.

The vaccines are safe. This includes their use in people with HIV/AIDS. While an earlier version of the vaccine was linked to intussusception, the current versions are not. Older recommendations were to avoid rotavirus vaccination in babies who have had intussusception. The vaccines are made from weakened rotavirus.

The vaccine first became available in the United States in 2006. It is on the World Health Organization’s List of Essential Medicines. As of 2013, there are two types of vaccine available globally, Rotarix and RotaTeq. Others are used in some countries.