x^2+y^2-6x-4y+12=0(x-3)^2 + (y-2)^2 = 1圆心(3,2) 半径 1(1)若直线斜率存在设切线的斜率是k所以y = k(x-2)kx - y -2k =0圆心到此直线距离等于圆的半径1所以|3k-2-2k|/根号(k²+1) = 1k = 3/4（2）若直线斜率不存在由图形可知x = 2也与圆相切 综上所述x = 23x-4y-6 = 0
