The equation contains five terms. All of them should have the same dimensions. Since `[x]=` length, each of the remaining for m,ust have the dimension of length.
Thus, `[a]=length=L`
` [bt]=L, or, [b]=LT^-1`
`[ct^2]=L, or [c]=LT^-2`,
and `[dt^3]=L, or, [d]=LT^(-3)`.