N
nganhoa98


1.Tìm x:
a)15*16+16*17+17*18+18*19+...+20010*20011
b)(1*2+2*3+3*4+...+2009*2010)*x/26950=90/7
2. Tính A=(1+7/9)*(1+7/20)*(1+7/33)*...*(1+7/240)
a)15*16+16*17+17*18+18*19+...+20010*20011
b)(1*2+2*3+3*4+...+2009*2010)*x/26950=90/7
2. Tính A=(1+7/9)*(1+7/20)*(1+7/33)*...*(1+7/240)