1) (4х - 3у)(4х+3у)+ (3х +4у)(4у - 3х)= 16х^2(в квадрате)+12ху-12ху-9у^2+12ху-9х^2+16у^2-12ху=7х^2+7у^2=7(х^2+y^2)
2) (х+2)² - (х-3)(х+3)=х^2+4х+4-(х^2+3х-3х-9)=х^2+4х+4-х^2-3х+3х+9=4х+13
3) (7а - 5b)(7a + 5b) - (4a + 7b)²=49а^2+35аb-35ab-25b^2-(16a^2+56ab+49b^2)=49а^2+35аb-35ab-25b^2-16a^2-56ab-49b^2=33a^2-56ab-74b^2
4) (у - 2)(у+3) - (у -1)² + (5 - у) (у +5) = у^2+3у-2у-6-(у^2-2у+1)+5у+25-у^2-5у=у^2+3у-2у-6-у^2+2у-1+5у+25-у^2-5у=-у^2+3у+18
квадрате) + (2b +10)x +4=0 имеет только один корень? решите уравнение х+3 + х-3 + 4(х+6) =0 х-3 х+3 9 - х( в квадрате) решите
Topic 1.Your school magazine is organizing a competition for best articles among school learns. You have to write an article about latest scientific news. Your article should include the following information:
-what exactly has happened;
- the place where it occurred;
-its potential effects/results.
Topic 2.Your school magazine is organizing a competition for best articles among school learns. You have to write an article about a deadly natural disaster. Your article should include the following information:
-the type of a natural disaster and its description;
-the place where it occured;
-the description of its consequences.
Writing Task 2.
Answer the following questions:
1.Do you like science? Why?
2.How will science change the world in the next 100 years?
2.What has science done for humankind?