Question

​​Ix-1l + lx-2l + lx-3l +...........+lx-100l = 2500

Giúp mik nhek

Answer 1

Đặt A=/x-1/+/x-2/+/x-3/+...+/x-100/

Ta có:A=/x-1/+/x-2/+/x-3/+...+/x-100/

\(\Rightarrow\)A=-(x-1+x-2+x-3+...+x-100) hoặc A=x-1+x-2+x-3+...+x-100

Th1:A=-x+1-x+2-x+3-...-x+100

A=(-x-x-x-...-x)+(1+2+3+...+100)

A=-100x+5050

Mà A=2500

Hay -100x+5050=2500

-100x=2500-5050

-100x=-2550

100x=2550

x=\(\frac{51}{2}\)

Th2:A=x-1+x-2+x-3+...+x-100

A=(x+x+...+x)-(1+2+3+...+100)

A=100x-5050

Mà A=2500

Hay 100x-5050=2500

100x=2500+5050

100x=7550

x=\(\frac{151}{2}\)

Answer 2

ai jup vs