y"/y' =(dy'/dx)/y'=(dy'/y')/dx = 5dy'/y'=5*dx两边同时积分，可以得到：ln(y') = 5x + C0因此，y'=dy/dx = e^(C0) * e^(5x) = C'*e^(5x)所以，dy = C'* e^(5x) *dx两边再同时积分，得到：y = C'* (1/5) * e^(5x) + C = C1 * e^(5x) + C
