\(a,2016:\left[25-\left(3x+2\right)\right]=3^2.7\)
\(\Rightarrow2016:\left[25-\left(3x+2\right)\right]=9.7\)
\(\Rightarrow2016:\left[25-\left(3x+2\right)\right]=63\)
\(\Rightarrow25-\left(3x+2\right)=2016:63\)
\(\Rightarrow25-\left(3x+2\right)=32\)
\(\Rightarrow3x+2=25-32\)
\(\Rightarrow3x+2=-7\)
\(\Rightarrow3x=-7-2\)
\(\Rightarrow3x=-9\)
\(\Rightarrow x=-9:3\)
\(\Rightarrow x=-3\)
Vậy `x = -3`
a: \(2016:\left[25-\left(3x+2\right)\right]=3^2\cdot7\)
=>\(2016:\left[23-3x\right]=9\cdot7=63\)
=>23-3x=2016:63=32
=>3x=23-32=-9
=>x=-3
b: \(\left(1-2+3-4+...+97-98+99\right)\cdot x=-100\)
=>\(x\cdot\left[\left(1-2\right)+\left(3-4\right)+...+\left(97-98\right)+99\right]=-100\)
=>\(x\left(-1-1-1-...-1+99\right)=-100\)
=>50x=-100
=>x=-2