Let's perform the synthetic division
Divide by 2
color(white)(aaaa)-1/2|color(white)(aaaa)1color(white)(aaaa)+3/2color(white)(aaaaaa)0color(white)(aaaaaa)2
color(white)(aaaaaaaa)|color(white)(aaaa)color(white)(aaaaa)-1/2color(white)(aaaaa)-1/2color(white)(aaaa)1/4
color(white)(aaaaaaaaa)_________________________________________________________##
color(white)(aaaaaaaa)|color(white)(aaaa)1color(white)(aaaaaa)1color(white)(aaaaaa)-1/2color(white)(aaaaa)color(red)(9/4)
The remainder is =(9/2) and the quotient is =(x^2+x-1/2)
(2x^3+3x^2+4)/(2x+1)=(x^2+x-1/2)+(9/4)/(x+1/2)
(2x^3+3x^2+4)/(2x+1)=(x^2+x-1/2)+(9/2)/(2x+1)