Question

[Trần Ngọc Bảo Chi]

Tìm x:

a) 720:[41-(2.x-5)]=2³.5

b) (x+1)+(x+2)+(x+3)+...(x+100)=5750

Answer 1

[Vũ Cao Minh⁀ᶦᵈᵒᶫ ( ✎﹏IDΣΛ亗 )]

\(\left(x+1\right)+\left(x+2\right)+\left(x+3\right)+...+\left(x+100\right)=5750\)

\(\left(x+x+x+...+x\right)+\left(1+2+3+...+100\right)=5750\)

\(\Rightarrow100x+5050=5750\Rightarrow x=5750-5050\)

\(100x=700\Rightarrow x=700:100=7\)

Answer 2

[Lily]

\(a,\text{ }720\text{ : }\left[41-\left(2x-5\right)\right]=2^3\cdot5\)

\(720\text{ : }\left[42-2x+5\right]=8\cdot5\)

\(720\text{ : }\left[42+5-2x\right]=40\)

\(720\text{ : }\left[47-2x\right]=40\)

\(47-2x=720\text{ : }40\)

\(47-2x=18\)

\(2x=47-18\)

\(2x=29\)

\(x=\frac{29}{2}\)