How we got different values of a and v on using different values of X. Have not understood steps

Hy ritu.. 1st of all dont take physics as a set of eqautions... It is much different than that.. An SHM should be thought in mind while thinking it.. At x=0 when the body is at centre then it`s velocity is maximum, and the maximum velocity is Aw, and it`s acceleration is 0 hence its force is 0.. And when x=a, where a is its amplitude, it`s acceleration is maximum and it`s velocity is 0... U can imagine it just like a simple pendulum.. Hope U like it..