utility function

Q.Given Yue’s utility function U (x,y) = 10x + 7y 
1.Is MRSx,y diminishing, constant, or increasing as the consumer substitutes x for y along an 
indifference curve? Explain
Q.Di’s utility function is U(x,y) = x^2 y^0.5
1.Does the marginal utility of x diminish, remain constant, or increase as the consumer buys more x? 
Explain