MATLAB GRADER HELP

I need help solving this question - Problem 1.5, and figuring out why I am getting an error. I checked the solution manual and the answer is same as mine but I am still getting an erro on MATLAB grader.

Script 1 x=2; 2 y=-1; 3 a=(2*x^3)^(1/4) 4 x=2; 5 y=-1; 6 b=(2xy^3)^(1/4) Previous Assessment: 0 of 2 Tests Passed > X Check a) (Pretest) Variable a has an incorrect value. > X Check b) (Pretest) Variable b has an incorrect value. 1.5 Suppose that x = 2 and y = -1. Evaluate the following expressions using MATLAB (a) V2x3 (b) V2y3 Note that MATLAB evaluates expressions with complex or imaginary answers transparently