If the area of the triangle formed by the image of the first-order function y = - 2x + B and the two coordinate axes is 9, then B=______ .

If the area of the triangle formed by the image of the first-order function y = - 2x + B and the two coordinate axes is 9, then B=______ .

The intersection coordinates of the line y = - 2x + B and the X axis are (B2, 0), and the intersection coordinates of the line y axis are (0, b). According to the area of the triangle is 9, we get 12 | B2 | · | B | = 9, that is, B24 = 9, and the solution is m = ± 6. So the answer is: ± 6