neu a-b ma b =4 va a>9 thi a-b < c+d c>76 va d=95 vay tong lai + cho 1695 + 6356 = may vay cac bn kho qua
Chon cau tra loi dung Neu a+b/b+c=c+d/d+a thi
a)a phai bang c
b)a=c hay a+b+c+d=0
c)a+b+c+d phai bang 0
d)a+b+c+d khac 0 neu a=c
Cho a;b;c thuoc Z b;d;c>0 .CMR:
Neu a>b thi a/b>a+c/b+c
Neu a<b thi a/b<a+c/b+c
Cho hai so huu ti a/b va c/d (b>0, d>0). Chung to rang :
a, Neu a/b < c/d thi ad<cd
b, Neu ad<bc thi a/b < c/d
cho a\b=c\d neu a+b\c-d=c+d\c-d
CMR neu [a+b+c+d]*[a-b-c+d]=[a-b+c-d]*[a+b-c-a] thi a/c=b/d
CMR ta co ti le thuc a/b=c/d neu dang thuc sau (a+b+c+d)(a-b-c+d)=(a-b+c-d)(a+b-c-d)
CMR ta co ti le thuc a/b=c/d neu dang thuc sau (a+b+c+d)(a-b-c+d)
Chug to rag neu a/b <c/d (b>0,d>0) thi a/b < a+c/b+d <c/d
