\(2x-1=-\frac{1}{2}x+4\Leftrightarrow x=2\Rightarrow M\left(2;3\right)\)
\(N\left(0;-1\right);P\left(0;4\right)\)
\(\Rightarrow\overrightarrow{NP}=\left(0;5\right)\Rightarrow NP=\sqrt{0+25}=5\)
\(\Rightarrow S_{MNP}=\frac{1}{2}NP.MK\)
Vì \(x_M=2\Rightarrow MK=2\)
\(\Rightarrow S_{MNP}=\frac{1}{2}.2.5=5\left(đvdt\right)\)