cho A =1+2^2018+3^2017+4^2016+...+2018^2+2019,B=1+2^2017+3^2016+...+2017^2+2018,chứng tỏ giá trị biểu thức A-3B dương

cho A =1+2^2018+3^2017+4^2016+...+2018^2+2019,B=1+2^2017+3^2016+...+2017^2+2018,chứng tỏ giá trị biểu thức A-3B dương

1+2018+2*2017+3*2016+..........................+2016*3+2017+2+2018*1

1+(1+2)+(1+2+3)+..........................(1+2+3+...............+2017+2018

tính nhanh:

a) (2016*2017+2018*2+2015):[(2018*2017-2017*2015)+2016]

b)2018*20182017-2017*20182018

c)1+2-3-4+5+6-7-8+...+298-299-300+301+302

1+2+3+4+...+2016+2017+2018

1+2+3+4+...+2016+2017+2018

1/2018 + 2/2018 + 3/2018 +............+ 2016/2018+ 2017/2018

Tính :A= [(2018/1)+(2017/2)+(2016/3)+(2015/4)+...+(4/2015)+(3/2016)+(2/2017)+(1/2018)]/[(2019/1)+(2019/2)+(2019/3)+(2019/4)+...+(2019/2015)+(2019/2016)+(2019/2017)+(2019/2018)+(2019/2019)]

a)A=/x+7/+/x^2-169/-/x-2018/

b)B=[2018/2+2018/3+2028/4+.....+2019/2018]:[1/2018+2/2017+3/2016+......+2018]

Tính :A= [(2018/1)+(2017/2)+(2016/3)+(2015/4)+...+(4/2015)+(3/2016)+(2/2017)+(1/2018)]/[(2019/2)+(2019/3)+(2019/4)+(2019/5)+...+(2019/2015)+(2019/2016)+(2019/2017)+(2019/2018)+(2019/2019)]

Tìm x,y thoả mãn

/x-2017/+/y-2018/ <=0

/3.x-y/^5+10./y+2/3/^7 <=0

c,1/2.(3/4.x-1/2)^2018+2017/2019./4/5.y+6/25/<=0

d,2017./2x-y/^2018+2018./y-4/^2017<=0

giúp em vs m.n ưi,mai em nộp ùi