Question

So sánh 2 số hữu tỉ. Cho a,b ∈ z \(\frac{a}{b}\) và \(\frac{a+2019}{b+2019}\)

Answer 1

TH1: a < b

=> 2019a < 2019b

=> ab + 2019a < ab+ 2019b

=> a(b+2019) < b(a+2019)

=> a/b < (a+2019)/(b+2019)

TH2: a = b

=> a/b = (a+2019)/(b+2019)

TH3: a > b

=> ab + 2019a > ab+ 2019b

=> a(b+2019) > b(a+2019)

=> a/b > (a+2019)/(b+2019)

Answer 2

đúng ko moonshine

đầu tiên: a < b

=> 2019a < 2019b

=> ab + 2019a < ab+ 2019b

=> a(b+2019) < b(a+2019)

=> a/b < (a+2019)/(b+2019)

2: a = b

=> a/b = (a+2019)/(b+2019)

3: a > b

=> ab + 2019a > ab+ 2019b

=> a(b+2019) > b(a+2019)

=> a/b > (a+2019)/(b+2019)

Answer 3

TH1: a < b

=> 2019a < 2019b

=> ab + 2019a < ab + 2019b

=> a (b + 2019) < b (a + 2019)

=> \(\frac{a}{b}\) < \(\frac{a+2019}{b+2019}\).

TH2: a = b

=> \(\frac{a}{b}\) = \(\frac{a+2019}{b+2019}\).

TH3: a > b

=> ab + 2019a > ab + 2019b

=> a (b + 2019) > b (a + 2019)

=> \(\frac{a}{b}\) > \(\frac{a+2019}{b+2019}\).

Chúc bạn học tốt!