Question

(x+1)+(x+2)+(x+3)+...+(x+500)=1500000

Answer 1

(x + 1) + (x + 2) + (x + 3) + ... + (x + 500) = 1500000

=> x + 1 +x + 2 + x + 3 + ... + x + 500 = 1500000

=> (x + x + ... + x) + (1 + 2 + 3 +... + 500) = 1500000

Số số hạng là : (500 - 1) : 1 + 1 = 500

Tổng : (1  + 500).500 : 2 = 125250

=> 500x + 125250 = 1500000

=> 500x = 1374750

=> x = 2749,5

Answer 2

( x + 1 ) + ( x + 2 ) + ( x + 3 ) + ... + ( x + 500 ) = 1500000

x + x + x + ... + x ( 500 số x ) + 1 + 2 + 3 + ... + 500 = 1500000

Phần 1 + 2 + 3 + ... + 500 có  : ( 500 - 1 ) / 1 + 1 = 500 ( số hạng )

x * 500 + ( 500 + 1 ) * 500 / 2 = 1500000

x * 500 + 125250 = 1500000

x * 500 = 1500000 - 125250

x * 500 = 1374750

x = 1374750 / 500 = 2749,5

Answer 3

                                                     Bài giải

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+500\right)=1500000\)

\(x+1+x+2+...+x+500=1500000\)

\(\left(x+x+...+x\right)\left(1+2+...+500\right)=1500000\)

\(500x+[\left(500-1\right)\text{ : }1+1]\text{ }\left(500+1\right)\text{ : }2=1500000\)

\(500x+125250=1500000\)

\(500x=1500000-125250\)

\(500x=1374750\)

\(x=1374750\text{ : }500\)

\(x=2749,5\)