câu trl 2 nhé

    \(x+x+x+81=-3-x\)

⇔\(4x=-84\)

⇔\(x=-21\)

`x xx 95 + x + x : 0,25 = 7963`

`x xx (95 + 1 + 4) = 7963`

`x xx 100 = 7963`

`=> x = 79,63`.

\(x\times\left(95+1+4\right)=7963\)

\(100\times x=7963\)

\(x=79,63\)

`x xx95+x+x:0,25=102,34`

`x xx95+x+x xx4=102,34`

`x xx(95+1+4)=102,34`

`x xx100=102,34`

`x=102,34:100=1,0234`

`x xx 95 + x + x :0,25 = 102,34`

`x xx 95 + x + x xx 4 = 102,34`

`x xx ( 95+1+4)=102,34`

`x xx 100 = 102,34`

`x = 102,34 : 100`

`x = 1,0234`

\(x\left(45+1+54\right)=9872\)

\(x\times100=9872\)

\(x=9872:100\)

\(x=98.72\)

X x45 + X +X x 54 =9872

X x45 + Xx1 +Xx54=9872

X x ( 45 + 1 + 54)   = 9872

X x           100         = 9872

X                             = 9872 : 100

X                             = 98,72

x(x+1)-(x-1)(x+2)=8

\(\Leftrightarrow\)\(x^2+x-x^2-2x+x+2=8\)

\(\Leftrightarrow0x=6\left(ptvn\right)\)

\(\Rightarrow S=\varnothing\)

`x:0,25+x:0,5+x+x xx93=24,6`

`x xx4+x xx2+x+x xx93=24,6`

`x xx(4+2+1+93)=24,6`

`x xx100=24,6`

`x=24,6:100`

`x=0,246`

`x+(x+1)+(x+2)+...+(x+30)=1240`

`=> (x + x + x + ... + x) + (1 + 2 + 3 +... + 30) = 1240`

`=> 31x + 465 = 1240`

`=> 31 x = 1240 - 465`

`⇒ 31x = 775`

`⇒ x = 775 : 31` 

`⇒ x = 25`

\(x+\left(x+1\right)+\left(x+2\right)+...+\left(x+30\right)=1240\\ \left(x+x+...+x\right)+\left(1+2+...+30\right)=1240\\ 31x+465=1240\\ 31x=1240-465\\ 31x=775\\ x=775:31\\ x=25\)

x:125=\(\frac{69}{115}\)

x=\(\frac{69}{115}\times125\)

x=75

mình ko biết làm