A Motion in straight line

a particle moving with uniform acceleration has its final velocity [v=(150+8x)1/2] m/s where x is the distance travelled by the body. Then the acceleration is
​1) + 4 m/s2
​2) – 4 m/s2
​3) + 8 m/s2
​4) – 8 m/s2
Answer: + 4 m/s2