化简求值：(3a-7)(3a+7)-2a(2/3a-1)其中a=-3

化简求值：(3a-7)(3a+7)-2a(2/3a-1)其中a=-3
化简求值：(3a-7)(3a+7)-2a(2/3a-1)其中a=-3

化简求值：(3a-7)(3a+7)-2a(2/3a-1)其中a=-3
(3a-7)(3a+7)-2a(3a/2-1)
=（3a）²-7²-（3a²-2a）
=9a²-49-3a²+2a
=6a²+2a-49
=6×9+2×（-3）-49
=54-6-49
=-1