The addition sign between the sets of parentheses means to add the two equations together by combining like terms
There is only one term raised to the 3rd power so that remains the same.
Next you have -1/2x ^2 + x ^2 = 1/2x ^2
Then x + -x/4 = 3/4x
And -5 is the only term with no variable so that remains the same.
Now combine into one line:
X ^3 +1/2x^2 + 3/4x -5