Given that the function y = √ ax + 1 (a is a constant and a < 0) is meaningful in the interval (- ∞, 1], the value range of real number a is obtained Wait for the line again. OK, there's an additional line~ y=√（ax+1）

Given that the function y = √ ax + 1 (a is a constant and a < 0) is meaningful in the interval (- ∞, 1], the value range of real number a is obtained Wait for the line again. OK, there's an additional line~ y=√（ax+1）

This problem has a critical condition. I will tell you slowly that y = √ ax + 1 is a meaningful function, that is, ax + 1 ≥ 0. If ax + 1 can be regarded as f (x), then a < 0 can draw an image, that is, a straight line passing through (0,1) point with a negative slope, then it must have an intersection with the X axis, ax + 1 ≥ 0. This problem can be transformed into a line passing through X ∈ (-)