If x is real, the expression x2+2x−11x−3 takes all real values except those which lie between a and b, then a and b are

Lety=x2+2x−11x−3⇒xy−3y=x2+2x−11⇒x2+(2−y)x+(3y−11)=0⇒(2−y)2−4(3y−11)≥0⇒4+y2−4y−12y+44≥0⇒y2−16y+48≥0⇒y2−12y−4y+48≥0⇒ (y−4)(y−12)≥0⇒ y≤4 ory≥12