A.1+x2=cy B.(1+x2)(3+2y)=c C. D.(1+x2)2(3+2y)=c
A.y″-2y′-3y=0 B.y″+2y′-3y=0 C.y″-3y′+2y=0 D.y″+2y′+y=0
A.y=c(y1-y2) B.y=c(y1+y2) C.y=y1+c(y1+y2) D.y=y1+c(y1-y2)