Question

[Công chúa Aikatsu]

Tìm x :

a) 5 - [ x + 1 ] = 29

b) ( - 1 ) + 3 + ( - 5 ) + 7 + ( - 9 ) + ... + x = 600

Answer 1

[Nguyễn Thanh Hằng]

a) \(5-\left[x+1\right]=29\)

\(x+1=5-29\)

\(x+1=-24\)

\(x=-24-1\)

\(x=-25\)

Vậy \(x=-25\) là giá trị cần tìm

b) \(\left(-1\right)+3+\left(-5\right)+7+\left(-9\right)+........+x=600\)

\(\Rightarrow\left[\left(-1\right)+3\right]+\left[\left(-5\right)+7\right]+............+\left[-\left(x-2\right)+x\right]=600\)

\(\Rightarrow2+2+2+.......+2=600\)

\(\Rightarrow2\left(1+1+......+1\right)=600\)

\(\Rightarrow1+1+........+1=300\)

Số dấu ngoặc [] là :

\(\dfrac{x-3}{4+1}\)

\(\Rightarrow\dfrac{x-3}{4+1}=300\)

\(\Rightarrow\dfrac{x-3}{4}=299\)

\(\Rightarrow x-3=299.4\)

\(\Rightarrow x=299.4+3\)

\(\Rightarrow x=1199\)

Answer 2

[Mashiro Shiina]

\(5-\left|x+1\right|=29\)

\(\left|x+1\right|=5-29\)

\(\left|x+1\right|=-24\Leftrightarrow x\in\left\{\varnothing\right\}\)