Предмет: Алгебра, автор: bkv321089

Помогите, пожалуйста!!! Очень срочно
(решить системы ) ​

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Автор ответа: Universalka
1

\displaystyle\bf1)\\-\left \{ {{x^{2} +y^{2} =25} \atop {x^{2} +y=5}} \right. \\---------\\y^{2} -y=20\\\\y^{2} -y-20=0\\\\Teorema \ Vieta:\\\\y_{1} =5 \  \ ; \  \ y_{2} =-4\\\\1) \ x^{2} =5-y=5-5=0\\\\x=0\\\\2) \ x^{2} =5-y=5-(-4)=5+4=9\\\\x=\pm 3\\\\Otvet:(0 \ ; \ 5) \ , \ (-3 \ ; \ -4) \ , \ (3 \ ; \ -4)

\displaystyle\bf2)\\\left \{ {{y=x^{2} +4x} \atop {y=-2x+8}} \right. \\\\x^{2} +4x=-2x+8\\\\x^{2} +6x-8=0\\\\D=6^{2} -4\cdot(-8)=36+32=68=(2\sqrt{17} )^{2} \\\\x_{1} =\frac{-6-2\sqrt{17} }{2} =-3-\sqrt{17}\\\\\\x_{2} =\frac{-6+2\sqrt{17} }{2} =\sqrt{17} -3\\\\y_{1}=-2\cdot(-3-\sqrt{17} )+8=6+2\sqrt{17} +8=14+2\sqrt{17} \\\\y_{2}=-2\cdot(\sqrt{17}-3 )+8=6-2\sqrt{17} +8=14-2\sqrt{17} \\\\Otvet:(-3-\sqrt{17}  \ ; \ 14+2\sqrt{17} ) \ , \ (\sqrt{17} -3 \ , \ 14-2\sqrt{17} )

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School uniform

A great fight still goes on. The question is: should students wear school uniform? As with most things, there are two sides to the debate. Some people say that all schools should introduce uniforms. Others are sure that school uniforms are old-fashioned. However, both arguments have experts on their side. There is no clear answer. Let's look at the pros and cons of it.

Many experts believe that students who wear school uniforms study much better than those who don’t. This is because you don't have to worry about what you are wearing each day. As a result your attention improves and you learn to concentrate better on your studies. Wearing a uniform in calming colours makes you feel more serious and responsible.

They say if you wear a uniform then you won't behave in a violent or inappropriate way at school. A uniform is a rule and rules must be obeyed. Research showed that students in uniforms don't play as many tricks on their classmates, tease or bully them as much as their casually dressed mates.

Everyone wants to look their best and better than their classmates. Everybody wants to be popular and wear the latest fashions. However, not all students have enough money to buy stylish clothes. Uniforms make them all equal, social differences are not seen. No one wears expensive brands. Everyone wears the same thing, exactly the same brand. With a uniform, there is less competition in class.

School uniforms, however, are not always cheap for parents, especially if there are two or more children in a family and they all go to school. Parents can't buy any skirt or trousers they want. They can't shop in the sales either. What is more, many schools have several uniforms such as an everyday uniform, a formal uniform for special events and a uniform for P.E. classes.

Students in uniforms look the same. Uniforms don't give students individuality so they have to look for other opportunities to express themselves. For example, they might start using make-up early, behaving badly or wearing bright accessories as a reaction against it. It’s not the answer.

Finally, there's comfort. Lots of students complain that they feel uncomfortable when they wear uniforms in class. Some children have sensitive skin and like to wear 100% cotton clothes. Uniforms are often made from synthetics, such as polyester which is harmful for a child’s skin, especially if the child spends the whole day at school.

1.Students in uniforms try to find ways to look different.
1)True
2)False
3)Not stated

2.Fashion designers create collections of school uniforms.
1)True
2)False
3)Not stated

3.A school uniform can improve students’ marks.
1)True
2)False
3)Not stated

4.Grey is the best colour for a school uniform.
1)True
2)False
3)Not stated

5.Uniforms can be expensive for parents.
1)True
2)False
3)Not stated

6.All uniforms are made of natural materials.
1)True
2)False
3)Not stated

7.A uniform makes students aggressive.
1)True
2)False
3)Not stated

8.There are different opinions about school uniform.
1)True
2)False
3)Not stated
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