As shown in the figure, the parabola y = - X & # 178; + 2 (k-1) x + K + 1 intersects the X axis at two points a and B, and intersects the Y axis at point C. the length ratio of line OA to ob is 1:3 (1) Finding the analytic formula of parabola and the coordinates of two points a and B (2) The circle d with diameter AB intersects with the positive half axis of Y axis at point e. the tangent line of circle D is made through e, and the X axis intersects with point F. the coordinates of point F are calculated AB is on the opposite side of Y axis

As shown in the figure, the parabola y = - X & # 178; + 2 (k-1) x + K + 1 intersects the X axis at two points a and B, and intersects the Y axis at point C. the length ratio of line OA to ob is 1:3 (1) Finding the analytic formula of parabola and the coordinates of two points a and B (2) The circle d with diameter AB intersects with the positive half axis of Y axis at point e. the tangent line of circle D is made through e, and the X axis intersects with point F. the coordinates of point F are calculated AB is on the opposite side of Y axis

The root formula shows that the ratio of X1 to X2 is equal to plus or minus 3