Question

Tìm x biết (2x-1)+(4x-2)+(6x-3)+.....+(400x-200)-5+10+.......+ 1000                                       Giải giúp nha mơn nhìu  

Answer 1

(2x−1)+(4x−2)+...+(400x−200)=5+10+...+1000(2x−1)+(4x−2)+...+(400x−200)=5+10+...+1000

⇒(2x+4x+...+400x)−(1+2+...+200)⇒(2x+4x+...+400x)−(1+2+...+200)

=5.(1+2+...+200)=5.(1+2+...+200)

⇒x.[(400+2).200:2]−[(200.{200+1}):2]⇒x.[(400+2).200:2]−[(200.{200+1}):2]

=5.[(200.{200+1}):2]=5.[(200.{200+1}):2]

⇒x.40200−20100=100500⇒x.40200−20100=100500

⇒40200x=120600⇒40200x=120600

⇒x=3⇒x=3

Vậy x=3.

Answer 2

cho mình k đi bạn

Answer 3

\(\left(2x-1\right)+\left(4x-2\right)+...+\left(400x-200\right)=5+10+...+1000\)

\(\left(2x+4x+...+400x\right)-\left(1+2+...+200\right)\)

\(5\left(1+2+...+200\right)\)

\(x\left[\left(400+2\right).200:2\right]-\left\{\left[200.\left(200+1\right):2\right]\right\}\)

\(5.\left\{\left[200.\left(200+1\right)\right]:2\right\}\)

\(x.40200-20100=100500\)

\(x=3\)