If your CAS expression is typed with just ",x" at the end instead of ",x,y" a result is obtained. Is it the result you're looking for?
Also, please note that CAS is intended for exact and/or symbolic math, not decimal number approximations, which is what Home view is used for. Entering a decimal point anywhere in a CAS expression forces it to revert to approximate mode. If you want to use the full power of CAS, never include any decimal points anywhere in the inputs. If you type your expression in CAS using exact values (e.g. instead of -0.3 use -3/10), CAS will return an exact result instead of a decimal approximation.
Disclaimer: I don't work for HP. I just enjoy using their calculators.