Усони наклеек в 2 раза меньше ,чем у тони,а вместе у них 390 наклеек. сколько у

у сони-х наклеек

у тони-2х наклеек

составим уравнение:

х+2х=390

3х=390

х=130

след.у сони-130 наклеек

у тони =130*2=260 наклеек

1 способ

1)390: 3=130 н -у сони

2)130*2=260 н -у тони

 

2 способ. 

пусть у сони x наклеек, тогда у тони 2x

                    x+2x=390

                    3x=390

                    x=130 - наклеек у сони

                    2x = 2*130=260 - наклеек у тони

 

Question 1. what factors increase species richness community? species diversity of community depends on the following factors: 1) geographical location (moving from north to south in the northern hemisphere, and vice versa, in the southern island fauna usually poorer than on the mainland, and it is the poorer you are, the smaller the island and the more distant it is from the mainland); 2) climatic conditions (in areas with mild, stable climate, with abundant and regular rainfall, without strong frosts and seasonal temperature fluctuations species richness is higher than in areas in zones of severe climate); 3) the duration of the development (the more time has passed since the education community, the higher its species richness). question 2. what is the significance of rare species? to maintain the life of rare species require specific combinations of different environmental factors (temperature, humidity, soil composition, certain types of food resources and others), which largely depends on the normal functioning of the ecosystem. rare species provide a high level of species diversity and are the best indicators of the state of the community as a whole. question 3. what are the properties of community characterizes species diversity? diversity of species is an indicator of well-being of the community or to the ecosystem as a whole, as it often decrease indicates a problem much earlier than changes in the total number of living organisms. species diversity is a sign of sustainability of the communities, i.e. the more diversity, the more stable is the community to sudden changes of environmental conditions. this is because in the case of the disappearance of any species is another view, close to the specialization eliminated from the community. question 4. what is a food chain and food web? what is their value? different types of organisms in the community are closely interrelated food links. for any community can make a chart of all the food interconnections food web. food network consists of several food chains. the simplest example of a food chain: the plant - растительноядное insect - насекомоядная bird - bird of prey. for each of the food chains forming the food web, transmitted energy and matter, i.e., is a material-energy exchange. implementation of all the links in the community, including food, contributes to the maintenance of its integrity.