The range of function - X & # 178; + 2x + 4 is

The range of function - X & # 178; + 2x + 4 is

solution
-x²+2x+4
=-(x²-2x)+4
=-(x²-2x+1)+1+4
=-(x-1)²+5
When x = 1, the maximum value is 5
The value range: (- ∞, 5]