x2−(a+1)x+29=0 1(0,3) p=0,q=3
For exactly one root
f(p).f(a)<0
⇒f(a)×f(3)<0
⇒2a×[9−(a+1)3+2a]<0
⇒2a(9−3a−3+2a)<0
⇒2a(6−a)<0
a∈(−∞,0)∪(6,∞)