Suppose that q(x) is the quocient and n(x)=6x3+5x2+2x+1,d(x)=2x+3,r(x)=c0. Then q(x)d(x)+r(x)=n(x) Putting q(x)=ax2+bx+c (Here q(x) degree must be 3−1 because d(x) degree is 1. By the same reason r(x) degree is 0).
After multiplication of q(x)d(x)+r(x)−n(x)=0 we get: (2a−6)x3+(3a+2b−5)x2+(3b+2c−2)x+3c+c0−1=0. This equation must be identically null for all x. Solving for a,b,c,c0 we obtain: q(x)=3x2−2x+4,r(x)=−11