Let's judge y 1=(x+ 1) first. Monotonicity and monotone interval can be simplified to get x to all real numbers.
When X=- 1, it is the symmetry axis of the original equation.
So according to the function image x
Y2= 1-x (x is not equal to 1) is always a decreasing function.
By definition (same increase but different decrease)
Therefore, when x is greater than negative 1, it is a decreasing function.
The increasing function when x is less than negative 1.