\(a,\)
\(=4x^2+4x-2xy-2y+x^2+2x+1+4x^2-4xy-y^2\)
\(=9x^2+6x-6xy-2y-y^2+1\)
\(b,\)
\(\dfrac{2x^2+3x-2}{2x-1}=\dfrac{\left(2x^2-x\right)+\left(4x-2\right)}{2x-1}\)
\(=\dfrac{x\left(2x-1\right)+2\left(2x-1\right)}{2x-1}\)
\(=\dfrac{\left(2x-1\right)\left(x+2\right)}{2x-1}\)\(=x+2\)