Wow! it looks like homework; what will you do the day of the exam?
Good to share your work and explain your difficulties.
Try this calculator, others available.
I worked this out and my solution to this is x(t) = -(t^2)/2 +2t - 2 +2.e^-t. Dont see why you'd have problems with solving this.
Where exactly do you need help with this ?
In this chapter we will start looking at second order differential equations. We will concentrate mostly on constant coefficient second order differential equations. We will derive the solutions for homogeneous differential equations and we will use the methods of undetermined coefficients and...
tutorial.math.lamar.edu
Note:
In your case, consider 2nd order autonomous differential equation.
Pierre