As shown in the figure, it is known that the image of quadratic function y = x2 + BX + C passes through points (- 1,0), (1, - 2). When y increases with the increase of X, the value range of X is___ ．

As shown in the figure, it is known that the image of quadratic function y = x2 + BX + C passes through points (- 1,0), (1, - 2). When y increases with the increase of X, the value range of X is___ ．

Substituting (- 1,0), (1, - 2) into the quadratic function y = x2 + BX + C, we get 1-B + C = 01 + B + C = - 2, the solution is b = - 1C = - 2, then the analytic expression of the quadratic function is y = x2-x-2. The axis of symmetry of the function is x = 12, so when y increases with the increase of X, the value range of X is x > 12

If the image of quadratic function y = x ^ 2 + BX + C is shown in the figure, then the function value y

y=x^2+bx+c
c=-4
-b/2a=-1
b=2
y=x^2+2x-4
When y = 0, x = - 1 - radical 5
X = radical 5-1
So the value range of X is - 1 - radical 5