double x;
double y;
cout << "Type a decimal point value for x" << endl;
cin >> x;
y = x + 3.0/4.0 - 2.0;
cout << "The value of y is " << y << endl;
This is not a complete program - you need some #include files and a main function.
I think you need to do a lot of reading, try the reference & articles section at the top left of this page. Do some tutorials. Google stuff you are unsure of.
x / 4 + 3 - 2 // according to order of the operators (if am not wrong)
Your parentheses enforce a different order of evaluation than the normal mathematical precedence, which is BEDMAS - Brackets, exponents, division, multiplication, addition, subtraction.
So the result of x + 3.0/4.0 - 2.0; is x + 0.75 - 2.0.
One shouldn't infer any other interpretation because varying results can be obtained by altering the parentheses, so one can only take the OP's expression at face value.
Edit: Pleas always use code tags - the <> button on the right.