设圆\({C}_{1}:{x}^{2}+{y}^{2}-2x+4y=4\)，圆\({C}_{2}:{x}^{2}+{y}^{2}+6x-8y-可可试卷app

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设圆\({C}_{1}:{x}^{2}+{y}^{2}-2x+4y=4\)，圆\({C}_{2}:{x}^{2}+{y}^{2}+6x-8y=0\)，则圆\({C}_{1}{C}_{2}\)有公切线___条.

参考答案：2