若a b满足3a²+3丨b丨=7,s=2a²-3lbl,则s的取值范围是

若a b满足3a²+3丨b丨=7,s=2a²-3lbl,则s的取值范围是
若a b满足3a²+3丨b丨=7,s=2a²-3lbl,则s的取值范围是

若a b满足3a²+3丨b丨=7,s=2a²-3lbl,则s的取值范围是
3丨b丨=7- 3a²
s=2a²-3lbl
= 2a²-(7- 3a²)
=5a²-7
a²≤7/3
取a²=0 a²=7/3
S=-7 S=14/3
则s的取值范围是-7≤S≤ 14/3