If the image of the function y = x ^ 2 + (a + 2) x + 3, X ∈ [a, b] is symmetric with respect to the line x = 1, then what is B-A equal to?

If the image of the function y = x ^ 2 + (a + 2) x + 3, X ∈ [a, b] is symmetric with respect to the line x = 1, then what is B-A equal to?

The axis of symmetry x = - (a + 2) / 2 = 1 of the function y = x ^ 2 + (a + 2) x + 3
a=-4
On the symmetry of line x = 1
a+b=2
Then B-A is equal to 10

It is known that the image of the function f (x) ax + BX + C is symmetric with respect to x = 1, and points (1, - 4), (2, - 3) seek the values of a, B, C on this function image
Second, if FX is greater than 0, find the value range of X

Because the image is symmetric with respect to x = 1, - B / 2A = 1
Then two points (1, - 4) (2, - 3) are substituted into the equation, a + B + C = - 4
4a+2b+c=-3
Three equations, three unknowns, solve a, B, C. second question: F (x) > 0, then let f (x) = 0. Find out two values of X, and the value range of X is between them