a/\(2x^2+3x-5=0\)
\(\Leftrightarrow2x^2-2x+5x-5=0\)
\(\Leftrightarrow2x\left(x-1\right)+5\left(x-1\right)=0\)
\(\Leftrightarrow\left(2x+5\right)\left(x-1\right)=0\)
=> x=1, x=-5/2
b/\(x^2+2x^2-8x+5=0\)
\(\Leftrightarrow3x^2-8x+5=0\)
\(\Leftrightarrow3x^2-3x-5x+5=0\)
\(\Leftrightarrow\left(3x^2-3x\right)-\left(5x-5\right)=0\)
\(\Leftrightarrow3x\left(x-1\right)-5\left(x-1\right)=0\)
\(\Leftrightarrow\left(3x-5\right)\left(x-1\right)=0\)
=> x=1, x=5/3