Can anyone help me solve this DE?

Could someone please help me solve this? I've tried and I just can't solve it. Thanks in advance for anyone who can help me!

A Particle moves along the x-axis toward the origin under the influence of a force of attraction at the origin which varies directly as the distance of the particle from the origin. At time t=0, the particle is 4 cm to the right of the origin and is moving toward the origin with a velocity of 20 cm per second and an acceleration of 64 cm per second squared.

(a) Find the position of the particle as a function of time.

(b) Find the velocity of the particle as a function of time.

(c) Find the acceleration of the particle as a function of time.

(d) Find the position of the particle at t=pi/4 seconds.

Britt