若代数式2a2+3a+1的值为6,则代数式6a2+9a+5的值为 .
:20.【解答】解:∵2a2+3a+1=6,即2a2+3a=5,
∴6a2+9a+5
=3(2a2+3a)+5
=20.
故答案为