Question

  giải giúp mik,chi tiết giúp mik nhé

Answer 1

\(a,9x^2-1-9x\left(x-2\right)=0\\ \Leftrightarrow9x^2-1-9x^2+18x=0\\ \Leftrightarrow18x-1=0\\ \Leftrightarrow18x=1\\ \Leftrightarrow x=\dfrac{1}{18}\\ b\left(x+1\right)^2-x\left(x+1\right)-3=0\\ \Leftrightarrow x^2+2x+1-x^2-x-3=0\\ \Leftrightarrow\left(2x-x\right)+\left(x^2-x^2\right)+\left(1-3\right)=0\\ \Leftrightarrow x-2=0\\ \Leftrightarrow x=2\)