Question

Пусть2,7<х<9и 1,5<у<3.Оцените 1)2ху 2)2ху+1 3)х/у+4

Answer 1

 2,7<x<9 * 1.5<y<3= 4.05<xy<27
 1)2(4.05)<2xy<2(27) = 8.1<2xy<54
 2) 1+8.1<2xy + 1 < 54 +1 = 9.1<2xy+ 1<55
 2.7/1.5<x/y<9/3=1.8<x/y<3
 3)4+1.8<x/y+4<3+4= 5.8<x/y+4<7