The weight of an object on earth is 350 newtons. on mars the same object would weigh 134 newtons. what is the acceleration due to gravty on the surface of mars, given that it is 9.8 meters/second2 on earth?

Mass will remain constant on both planet, let mass of the object be "m".
let x be the acceleration due to gravity on the surface of mars.
Weight of object on earth = m *g , where g is acceleration due to gravity on the surface of earth
⇒350 =  m *  9.8
⇒m = 350  /  9.8                        equation(1)
Weight of object on mars = m * x , where x is acceleration due to gravity on the surface of mars
134  =   m   *  x                           equation(2)
putting the value of m from equation (1) in equation(2) , we get,
x     =   (134  *  9.8) / 350
⇒  x   =   3.572 m/s²