如图,⊙M与x轴相交于点A(2,0),B(8,0),与y轴相切于点C,圆心M的坐标为 .
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计算:x3· x —3 = ______;a 6÷a2·a3 =___________;2 0 + 2—1 =______.
找规律填空: ……
若a+b="5," ab=6,则a2+b2=________