Question

Tìm x, y
a) 2 5/x = 21/x (x ∈ N*)

b) x/7 = 5/y (x; y ∈ Z, x > y)

Answer 1

a, bạn viết rõ đề ra nhé 

b, \(\Rightarrow xy=35\Rightarrow x;y\inƯ\left(35\right)=\left\{\pm1;\pm5;\pm7;\pm35\right\}\)

x	1	-1	5	-5	7	-7	35	-35
y	35	-35	7	-7	5	-5	1	-1

 

Answer 2

1+1=3