Am not sure at all how to do this, all i know is the intial guess the DE is

y''+ 5y'=30x^2

my intial guess is ax^2 +bx + c

the deritives are y'=2ax + b and y''=2a

then i get (2a) + 5(2ax+b)=30x^2 or 2a + 10ax + 5b=30x^2

10ax + 2a + 5b=30x^2

if i equate them dont i get a=b=0? or am i missing something any help appreciated thanks in advance!