Given that the image of the first-order function passes through a point (1,2), and the product of the abscissa of the intersection of the image and the x-axis and the ordinate of the y-axis is 9, the first-order function can be obtained

Given that the image of the first-order function passes through a point (1,2), and the product of the abscissa of the intersection of the image and the x-axis and the ordinate of the y-axis is 9, the first-order function can be obtained

The product of the abscissa of the intersection of the image and the X axis and the ordinate of the Y axis is 9
Coordinates of the intersection of image and X-axis (- B / K, 0)
Coordinates of the intersection of image and Y axis (0, b)
（-b/k）b=9
The analytic formula of a function y = KX + B substitutes the point (1,2) into 2 = K + B
The solution of the equation is k = - 4 or K = - 1, B = 6 or B = 3
Y = - 4x + 6 or y = - x + 3