general solution of the DE is
6. If $y = 1 - x + 6x^2 + 3e^x$ is a solution of a homogeneous fourth-order linear differential equation with constant coefficients, then the roots of the auxiliary equation are
7. If $y = c_1x^2 + c_2x^2 \ln x$, $x > 0$, is the general solution of a