\(d\left(O;d\right)=\dfrac{\left|0\cdot\left(m-1\right)+\left(-1\right)\cdot0+4\right|}{\sqrt{\left(m-1\right)^2+1}}=\dfrac{4}{\sqrt{\left(m-1\right)^2+1}}\)
Để d=2 thì \(\dfrac{4}{\sqrt{\left(m-1\right)^2+1}}=2\)
=>(m-1)^2+1=4
=>(m-1)^2=3
=>\(m=\pm\sqrt{3}+1\)