I need help answering this question using MATLAB with simple commands not advanced

Problem 3: Given the polynomial: x3 6x2 30 0 a) Use MATLAB to find all roots of this polynomial. b) Use MATLAB's polyval function to evaluate the above polynomial for the xvalues given: 12 12,4 -3] Problem 4: Use MATLAB built in functions to come up with sequence of commands to graphically estimate where, and then calculate the 3 roots (solutions) of the following function: fOx) e 1.5x sin(8nux) where -0.2 S x S 0.2