Answer
$2x^2 -3x +8$
Work Step by Step
Like terms must (1) be raised to the same power and (2) consist of the same variable (i.e. x and y are not like terms). It is also important to note that numbers are all like terms with each other when not multiplied by anything. Thus, combining like terms, we obtain:
$$ (7-5)x^2 -3x + 8 \\ 2x^2 -3x+8$$
