Representing and Analyzing SHM Practice Test

A block in SHM has equilibrium at $x=0$ and +$x$ upward. At one instant the block passes through $x=0$ moving upward. Which describes the acceleration at that instant?

A mass-spring oscillator has equilibrium at $x=0$ and +$x$ to the right. At $t=0$ the mass is at $x=0$ moving right. Which is true about its acceleration at $t=0$?