CMR 81^10-27^ 13-9^21 chia hết 225
CMR: 106 - 57 ⋮ 59
CHo A=1/2.2+1/4.4+1/6.6+...+1/2020.2020 CMR A<9/32
cho a/b=c/d CMR 2a+b/3a-b=2c+d/3c-a
CMR:
\(A=2222^{5555}+5555^{2222}⋮7\)
Cho a+b/a-b = c+d/c-d . CMR : a/b = c/d
CMR 0<a<1 Thì\(\sqrt{a}\)>a
Cho (4x-5y)/3 = (5z-3x)/4 = (3y-4z)/5. CMR: x/5=y/4=z/3
Cho a,b thuộc Z, a>b, b>0. CMR: a/b>a+2015/b+2015
