\(a,\Leftrightarrow\Delta=4\left(m+4\right)^2-4\left(m-4\right)\left(m-1\right)>0\\ \Leftrightarrow4m^2+32m+64-4m^2+20m+16>0\\ \Leftrightarrow52m+80>0\Leftrightarrow m>-\dfrac{20}{13}\\ b,\Leftrightarrow\Delta=\left(5m+6\right)^2-12\left(2m+3\right)\left(m+1\right)>0\\ \Leftrightarrow25m^2+60m+36-24m^2-60m-36>0\\ \Leftrightarrow m^2>0\\ \Leftrightarrow m\ne0\\ c,\Leftrightarrow\Delta=4\left(m+3\right)^2-4\left(m-5\right)\left(m-2\right)>0\\ \Leftrightarrow4m^2+24m+36-4m^2+28m-40>0\\ \Leftrightarrow52m-4>0\Leftrightarrow m>\dfrac{1}{13}\)